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FJG . I.--See also:

Flagellata. 1. Chlamydomonas pulvisculus, (Chrysomonadidae). See also:Half of a Ehr. (Chlamydomonadidae) See also:free- large See also:colony, the flagellates em-See also:swimming individual. bedded in a See also:common jelly. a = See also:nucleus. b =contractile vacuole. 0= See also:starch corpuscle. d = See also:cellulose investment. e =stigma (See also:eye-spot). 2.

Resting See also:

stage of the same, with fourfold See also:division of the See also:cell-contents. Letters as before. 3. Breaking up of the cell-contents into See also:minute biflagellate swarm-spores, which See also:escape, and whose See also:history is not further known. 4 Syncrypta volvox, Ehr. (Chrysomonadidae). A colony enclosed by a common gelatinous test c. a =stigma. b =vacuole(non-contractile). 5. Uroglena volvox, Ehr. 6.

Chlorogonium euchlosum, Ehr. (Chlamydomonadidae). a =nucleus. b =contractile vacuole. c =starch See also:

grain. d = eye-spot. 7. Chlorogonium euchlorum, Ehr. (Chlamydomonadidae).Copu lation of two liberated microgonidia. a =nucleus. b =contractile vacuole. d =eye-spot (so-called).

8. Colony of Dinobryon sertularia, Ehr. (Chrysomonadidae). 9. Haematococcus palustris, Girod (= Chlamydococcus, Braun, Protococcus, See also:

Cohn), one of the (Volvocidae), showing the inter-cellular connective fibrils. a nucleus. b= contractile vacuole. c =starch granule. 19. Two microgametes (spermatozoa) of Volvox globator, L. a= nucleus. b= contractile vacuole. 20.

Ripe asexually produced daughter-individual of Volvox See also:

minor, See also:Stein, still enclosed in the cyst of the partheno-gonidium. a= See also:young, partheno-gonidia. 21, 22. Trypanosoma sanguinis, Gruby (Haematoflagellates), from the See also:blood of Rana esculenta. a = nucleus; X 500. 23-26. See also:Reproduction of See also:Bodo caudatus, Duj. (Bodonidae), after Dallinger and Drysdale: 23, See also:fusion of several individuals (plasmodium); 24, encysted fusion-product dividing into four; 25, later into eight; 26, cyst filled with swarm-spores. 27. Distigma See also:proteus, Ehbg., O. F. See also:Muller (Euglenidae) ; X 440.

Individual with the two flagella, and strongly contracting hinder region of the See also:

body. 28. The same devoid of flagella. c, c =the two dark pigment spots (so-called eyes) near the mouth., 29. Oicomonas termo (Monas termo) Ehr. (one of the Oicomonadidae). c = See also:food-ingesting vacuole. d =food-particle; X440. 30. The food-particle d has now been ingested by the vacuole. 31. Oicomonas mutabilis, See also:Kent (Oicomonadidae), with adherent stalk. a = nucleus.

b = contractile vacuole. c =food-particle in food vacuole. 32, 33. Cercomonas crassicauda, Duj. (Oicomonadidae), showing two conditions of the pseudopodium-protruding tail. a =nucleus. b =contractile vacuoles. c =mouth. known generally as " plastids " or " chromatophores " impregnated with a lipochrome pigment, whether See also:

green (See also:chlorophyll), yellow or See also:brown (diatomin or some allied pigment), or again red (chlorophyll with phycoerythrin). In the active 'See also:condition of such coloured holophytic forms there is usually at least one anterior " eye-spot," of a refractive globule embedded behind in a collection of red pigment granules. The single anterior " flagellum tractellum " of so many of the larger forms acts by the bending over of its free end in consecutive meridians, so as to describe a hollow See also:cone with its See also:apex backwards: we may imitate this by bending the See also:head of a slender sapling See also:round and round while it is implanted in the See also:soil; and the result is to push the See also:water backwards, or in other words to pull the body forwards, the whole rotating on its See also:longitudinal See also:axis as it moves on (Y. Delage).

An anterior lateral trailing flagellum may modify this axial rotation, and help in steering. When the See also:

animal is at rest—attached by its See also:base or with its body so curved as to resist onward motion—the current produced by the tractellum will bring suspended particles up against the See also:protoplasm at its base of insertion. As noted by E. R. Lankester, the posterior flagellum of many Haemoflagellates, like that of the spermatozoon of Metazoa, propels the cell by a sculling See also:motion behind; he terms it a " pulsellum." Such flagellar motion is distinct from that of See also:cilia, which always move backwards and forwards, with a See also:swift downstroke and a slower recovery in the same See also:plane; though where the flagella are numerous they may behave in this 1 way, and indeed flagella agree with cilia in being See also:mere vibratory extensions of cytoplasm. Symmetrically placed flagella may have a symmetrical reciprocating motion like that of cilia. Many of the Flagellata are parasitic (some haematozoic); the See also:majority live in the midst of putrefying organic See also:matter in See also:sea and fresh See also:waters, but are not known to be active as agents of putrefaction. Dallinger and Drysdale have shown that the spores of Bodo and others will survive an exposure to a higher temperature than do any known Schizomycetes (Bacteria), viz. 2500 to 300° F4hr., for ten. minutes, although the adults are killed at 18o°. The Flagellata are for the most See also:part very minute; the Protomastigopoda rarely exceeding 2oµ in length. The Euglenaceae contain the largest See also:species, up to 130 µ in length, exclusive of the flagellum. Our See also:classification is modified from those of Senn (in Engler and Prantl, Pflanzenfamilien) and Hartog (in See also:Cambridge Natural History).

I. RHIZOFLAGELLATA (PANTOSTOMATA) Food taken in by pseudopodia at any part of the body. See also:

Order i.—HOLOMASTIGACEAE. Body homaxial with See also:uniform flagella. Multicilia (Cienkowski) ; Grassia (Fisch, in See also:frog's blood and gastric mucus). Order 2.—RHIZOMASTIGACEAE. Flagellum 1, 2 or few, diverging from anterior end. Mastigamoeba (F. E. Schulze). II. EUFLAGELLATA Food taken in at one or more definite mouth-spots, or by a true mouth, or by absorption; or See also:nutrition holophytic.

Order i.—PROTOMASTIGACEAE. Contractile vacuole See also:

simple, one or more, or absent; either holozoic, ingesting food by a mouth-spot (or 2 or more), saprophytic, or parasitic. See also:Family I.—OICOMONADIDAE. Flagellum 1, sometimes with a tail-like posterior prominence passing into a temporary flagellum, but without other cytoplasmic processes. Oicomonas (Kent) ; Ccrcomonas (Dujardin) (fig. 1, 32, 33) Codonoeca (See also:James-See also:Clark), with a gelatinous theca. Family 2.—BICOECIDAE. Differs from Oicomonadidae in a unilateral proboscidiform See also:process next the flagellum; often thecate and stalked, forming branched colonies, like Choanoflagellates in See also:habit. Bicoeca (J.-Cl.), Poteriodendron. Family 3.—CI30AN0FLAGELLIDAE (Choanoflagellata, Kent; Craspedomonadina, Stein). As in previous families, but with flagellum surrounded by an obconical or cylindrical rim of cytoplasm, at the base of which is the ingestive See also:area. The cells of this See also:group have the See also:morphology of the flagellate cells (choanocytes) of See also:sponges.

They are often colonial, and in the gelatinous colony of Proterospongia, the more See also:

internal cells (fig. 2, 15) pass into a definite " reproductive See also:state." Many stalked forms are epizoic on Entomostracan See also:Crustacea. (a) Naked forms often stalked: Monosiga (Kent), stalked solitary; Codosiga (Kent) (fig. 2, 3), stalked social; Desmarella (Kent), unstalked, and Astrosiga (Kent), stalked, See also:form floating colonies. (b) Forms enclosed in a See also:vase-like See also:shell: Salpingoeca (J.-Cl.) ; (fig. 2, 1, 6, 7) recalling the habit of Monosiga and See also:Cod siga; Polyoeca forming a branched free swimming colony. (c) Forms surrounded by a gelatinous sheath : Protero- spongia (Kent) (fig. 2, 15); Phalansterium (Cienk.) (fig. I, 12), has a slender cylindrical See also:collar, and a branching tubular stalk. FamilY4.—HAEMOFLAGELLIDAE. Formswithacomplexnuclear apparatus, and a See also:muscular undulating membrane with which one or two flagella are connected, parasitic in Metazoa (often in the blood). Trypanosoma (Gruby) (fig.

1, 21, 22), Her petomonas(Kent),Treponema (Vuillemin) ( = Spirochaete, auctt., nee. Ehrbg.). Family 5.—Am PHIMONADIDAE. Flagella 2 anterior, both directed forward, equal and similar; in stalk sheath, &c., often recalling Choanoflagellata, Amphimon.j (Kent), Diplomitus (Kent) ; Spongomonas (St.), with thick branching gelatinous sheath. Family 6.—MONADIDAE. Flagella 2 (3), anterior all directed forwards, one See also:

long the other (or 2) See also:accessory, See also:short. Monas (St.); Anthophysa (Bory) (fig. 2, 12, 13), with the stalk composed of the See also:accumulation of faeces at the hinder end of the cells of the colony. Family 7.—B0DONIDAE. Flagella 2 (or 3) I anterior, the other (i or 2) antero-lateral and trailing or becoming fixed at the end to form a temporary See also:anchor. Bodo (Ehrb.) (See also:figs. 1, 23-26 and 2, 1o).

B. See also:

lens is the " hooked " and B. saltans the " springing See also:monad " of Dallinger and Drysdale; Dallingeria (Kent) with a pair of Chrysomonadidae; See also:ordinary individual with widely separated test. a = nucleus. b =contractile vacuole. c =amylon nucleus (pyrenoid). 10. Dividing resting stage of the same, with eight fission See also:pro-ducts in the common test e. i I. A microgonidium of the same. 12. Phalansterium consociatum, Cienk. (Choanoflagellata); X325. Disk-like colony.

13. Euglena viridis, Ehr.; X 300 (Euglenidae). a= pigment spot (stigma). b =clear space. c =paramylum granules. d =chromatophor (endo- chrome See also:

plate). 14. Gonium pectorale, O. F. Muller (Volvocineae). Colony seen from the See also:flat See also:side; X 300. a= nucleus.

b =contractile vacuole. c =amylon nucleus. 15. Dinobryon sertularia, Ehr. (Chrysomonadidae). a= nucleus. b =contractile vacuole. c =amylon nucleus. d= free colourless flagellates, probably not belonging to Dinobryon. e=stigma (eye-spot). f =chromatophors. 16. Peranema trichophorum, Ehr.

(Peranemidae), creeping individual seen from the back; X 140. c =pharynx. d = mouth. 17. Anterior end of Euglena acus, Ehr., in See also:

profile. a = mouth. b =vacuoles. c =pharynx. d = stigma (eye-spot). e =paramylum-body. f=chlorophyll corpuscles. 18. Part of the See also:surface of a colony of Volvox globator, L.

See also:

ing the relation of the individual monads or flagellate zooids to the See also:stem d. 14. Tetramitus rostratus, Perty (Tetramitidae). a = nucleus. b = contractile vacuole. 1, Preterospongia Haeckeli, Saville Kent (Choanoflagellata) ; A social colony of about See also:forty flagellate zooids. a=nucleus. b =contractile vacuole. c =amoebiform cell sunk antero-lateral flagella; Costia necatrix (Leclerq) is also 3-flagellate; causes destructive epidemics in See also:fish-hatcheries. Family 8.—TETRAMITIDAE. Body pyriform, the pointed end posterior; flagella 4 anterior. Tetramitus (Perty) (T. calycinus of Kent, fig.

2, 11, 14), is the " calycine monad " of Dallinger and Drysdale; Trichomonas, See also:

Donne, possesses a longitudinal undulating membrane, and is an innocuous human See also:parasite; it is possibly related to H a e mo fl agellates on one See also:hand and to Trichonymphidae on the other. Family 9.—DISTOMATIDAE. Mouth-spots two, or one, with a distinct construction; fla- gella symmetri- cally arranged; nucleus bilobed or geminate. Hexamitus (Duj.) (fig. 2, 5), saprophytic and parasitic ; Trepomonas (Duj.), See also:freshwater; Mega-stoma (Grassi) ( = Lamblia of See also:Blanchard), with See also:con- stricted mouth- spot and blepha- roplast (kinetonucleus) parasitic in the small See also:intestine of Mammals, including See also:Man. Family Io.—TRIcIIo-NYMPHIDAE. Flagella numerous, sometimes accompanied by one or more undulating membranes; cytoplasm highly differentiated; contractile vacuole absent; all parasitic in in-sects (all except Lophomonas in Termites—the so-called See also:White Ants.) Lophomonas(St.) (fig. 2, 9); parasitic in the See also:cock- See also:roach ; Dinenympha (See also:Leidy), Pyrsonympha (Leidy) ; Trichenympha (Leidy) (fig. 3, z). Family II.—OPALINIDAE. Flagella short, numerous, ciliform, uniformly distributed over the flat See also:oval body; nuclei small, numerous, uniform. Only genus, See also:Opalina (Purkinje and Valentin) (fig.

3, 2-6), in See also:

bladder and See also:cloaca of the frog (usually regarded as an aberrant ciliate, but E. R. Lankester expressed doubts as to its position in the 9th edition of this See also:encyclopaedia). Order 2.—CHRYSOMONADACEAE. Contractile vacuole simple (in fresh-water forms) or absent; plastids yellow or brown always See also:present; reserves See also:fat. Family I.—CHRYSOMONADIDAE. Body naked, often amoeboid in active state, or sometimes with a See also:cup-like theca, a gelatinous investment, a See also:firm cuticle, or silicified shell; reserves fat or leucosin (starch in Zooxanthella); eye-spot present. Chromulina (Cienk.) often forms a See also:golden scum on tanks; Chrysamoeba (Klebs) ; Hydrurus (Agardh), theca of colony 6, 7. Salpingoeca urceolata, S. Kent (Choanoflagellata) :—6, with collar extended; 7, with collar retracted within the stalked cup. 8. Polytoma uvella, See also:Mull. sp.

(Chlamydomonadidae) . 9. Lophomonas blattarum, Stein (Trichonymphidae) from the intestine of Blatta orientalis. so. Bodolens, Mull. (Bodonidae), the wavy filament is a tractellum, the straight one is a trailing See also:

thread. II. Tetramitus sulcatus, Stein (Tetramitidae). 12. Anthophysa vegetans, O. F. Muller (Monadidae).

A typical, erect, shortly-branching colony stock with four terminal monad-clusters. 13. Monad cluster of the same in See also:

optical See also:section, show- 1. Salpingoeca fusiformis, S. Kent (Choanoflagellata). The protoplasmic body is See also:drawn together within the See also:goblet-shaped shell, and divided into numerous spores. 2. Escape of the spores of the same as monoflagellate and swarm-spores. 3. Codosiga umbellata, Tatem (Choanoflagellata) ; adult colony formed by dichotomous growth. 4. A single zooid of the same.

a= nucleus. b=contractile vacuole. c=the characteristic " See also:

col- See also:lar " of naked stream- ing protoplasm. 5. Hexamita inflata, Duj. (Distomatidae) ; normal adult. 1. Trichonympha agilis, Leidy, from gut of White See also:Ant (See also:Termite). 2. Opalina ranarum, Purkinje parasitic in frog rectum multinucleate adult. 3,4. Binary fissions of same, I-nucleat individual at final stage of fission. 5.

Same encysted dejected from rectum to be swallowed by See also:

tadpole. 6. Young 1-nucleate individual emerged from cyst, destined to grow, proliferating its nuclei to adult form. a = nucleus. b=food (?) particles in fig. I. within the colonial gelatinous test compared by S. Kent to a mesoderm cell of the sponges. d=similar cell reproducing by transverse fission. e=normal cells, with their collars contracted. f = substance of test. g = individual reproducing by multiple fission, producing microzoospores, comparable to the spermatozoa of sponges.

forming branching tubes, simulating a yellow Conferva in See also:

mountain torrents; Dinobryon (Ehrb.) (fig. I, 8, i5); Stylochrysalis (St.); Uroglena (Ehrb.); Syncrypta (Ehrb.), and Synura (Ehrb.) (fig. I, 5) form floating spherical colonies; Zooxanthella (randt), symbiotic as ' yellow cells " in See also:Radiolaria See also:Foraminifera, Millepora, and many See also:Actinozoa. Family 2.—COCCOLITHOPHORIDAE. Body invested in a spherical test strengthened by calcareous elements, tangential circular plates, " coccoliths," " discoliths," " cyatholiths," or radiating rods " rhabdoliths." These are often found in Foraminiferal See also:ooze and its fossil condition, See also:chalk; when coherent as in the See also:complete test, they are known as " coccospheres " and " rhabdospheres." Coccolithophora (Lohmann), Rhabdosphaera (See also:Haeckel), Order 3.—CRYPTOMONADACEAE. Contractile vacuole (in fresh-water forms) simple; plastids green, more rarely red, brown or absent; reserves starch; holophy See also:tic or saprophytic. Cryptomonas (Ehrb.); Paramoeba (Greeff) has yellow plastids and shows two cycles, in the one amoeboid, finally encysting to pro-duce a brood of flagellulae; in the other flagellate, and multiplying by longitudinal fission (it differs from Mastigamoeba in possessing no flagellum in the amoeboid state, though it takes in food See also:amoeba-See also:fashion) ; Chilomonas (Ehrb.). Order 4.—CHLOROMONADACEAE. Contractile vacuoles 1-3, a complex of variable arrangement; pellicle delicate; plastids discoid chlorophyll-bodies; reserves oil; eye-spot absent even in active state; holophytic or saprophytic, though with an anterior See also:blind tubular depression simulating a pharynx. Coelomonas (St.), Vacuolaria (Cienk.). Order 5.—EUGLENACEAE. Vacuole large, a See also:reservoir for one or more accessory vacuoles, contractile and opening to the surface by a See also:canal (" pharynx ") in which are planted one or two strong flagella; pellicle strong often striated; nucleus large, chromatophores green, complex or absent; reserves paramylum granules of definite shape, and oil; nutrition variable; body stiff or " metabolic," never amoeboid.

Among the true Flagellates these are the largest, few being below 40 and several attaining 130 µ in length of cell-body (excluding flagellum). Encysted condition common; the green forms sometimes multiply in this state and simulate unicellular See also:

Algae. Family 1.—EUGLENIDAE. Radial (monaxial) forms; nutrition saprophytic or holophytic, mostly one flagellate. (I) Chromatophore large; eye-spot conspicuous. Euglena (Ehrb.) (fig. 1, 13, 17), with flexible cuticle and metabolic movements (this is probably See also:Priestley's " green matter " through which he obtained See also:oxygen See also:gas)—a very common genus; Colacium (Ehbg.), in Its resting state epizoic on Copepoda, which it See also:colours green; Eutreptia (Perty), biflagellate; Ascoglena (St.); Trachelomonas (Ehrb.), with a hard brown cuticle; Phacus (Nitszche), with a firm rigid pellicle, often symmetrically flattened; Cryptoglena (Ehbg.). (2) Chromatephores absent. Astasia (Duj.), body metabolic; Menoidium (Perty), body not metabolic, somewhat inflected and crescentic; Sphenomonas (Stein), with a short accessory trailing flagellum 'in front peeled; Distigma (Ehbg.) (fig. 1, 27, 28), very metabolic, with two unequal flagella and two dark pigment spots. Family 2.—PERANEMIDAE. Bilaterally symmetrical, often creeping, pharynx highly See also:developed, with a firm See also:rod-like See also:skeleton, sometimes protrusible; nutrition saprophytic and holozoic.

Peranema (Ehbg.) and Urceolus (Mereschowsky), uni-flagellate creeping, very metabolic. Petalomonas (St.), uni-flagellate flattened with a deep ventral groove, not metabolic; Heteronema (Duj.) and Tropidoscyphus (St.), with a small accessory anterior trailing flagellum; Anisonema (Duj.) and Entosiphon (St.), with the trailing flagellum as long as the tractellum or even much longer. Order 6.—VOLVOCACEAE. Contractile vacuole simple anterior; cell always enclosed in a cellulose See also:

wall (sometimes gelatinous) perforated by the two (more rarely four, five) diverging anterior flagella; reserves starch; chlorophyll almost always present, except in Polytoma, sometimes masked by a red pigment; nutrition usually holophytic, rarely saprophytic, never holozoic. Brood-division in active state common, radial. Family I.—CHLAMYDOMONADIDAE. Cell-wall firm not gelatinous, rarely forming colonies. Fore-end of the body with two or four (seldom five) flagella. Almost always green in consequence of the presence of a very large single chromatophore. Generally a delicate shell-like envelope of membranous consistence. I to 2 simple contractile vacuoles at the base of the flagella. Usually one eye-speck.

Division of the protoplasm within the envelope may produce four, eight or more new individuals. This may occur in the swimming or in a resting stage. Also by more continuous fission microgametes of various sizes are formed. Conjugation is frequent. Genera.—Chlorangium (Stein), lacking green chlorophyll; Chlorogonium (Ehr.) (fig. 1, 6, 7); Polytoma (Ehr.) (fig. 2, 8); Chlamydomonas (Ehr.) (fig. I, 1, 2, 3); Haematococcus (Agardh) (= Chlamydococcus, A. Braun, Stein) ; Protococcus (Cohn, See also:

Huxley and See also:Martin) ; Chlamydomonas (Cienkowski), causes red See also:snow and " bloody See also:rain "; Carteria (Diesing), quadri-flagellate; Spondytomorum (Ehrb.), forming floating colonies; Coccomonas (St.); Phacotus (Perty) ; Zoochlorella (Brandt), is the name given to undetermined Chlamydomonads found multiplying in the resting state within and in symbiotic relation to other See also:Protozoa, to the fresh-water sponge, Ephydatia, See also:Hydra viridis, and to the Turbellarian, Convoluta viridis (in which last species the active form has been recognized as a Carteria). Family 2.—VoLVOCIDAE. Cell-wall gelatinous; always associated in colonies; cells, as in Family 1. The number of individuals See also:united to form a colony varies very much, as does the shape of the colony.

Reproduction by the continuous division of all or of only certain individuals of the colony, resulting in the See also:

production of a daughter colony (from each such individual). In some, probably in all, at certain times copulation of the individuals of distinct sexual colonies takes See also:place, without or with a differentiation of the colonies and of the copulating cells as male and See also:female. The result of the copulation is a resting zygospore (also called zygote or oospermo or fertilized See also:egg), which after a See also:time develops itself into one or more new colonies. Genera.—Gonium (0. F. Muller) (fig. I, 14); Stephanosphaera (Cohn) ; Pandorina (Bory de Vinc.) ; Eudor'na (Ehr.) ; Volvox (Ehr.) (fig. I, z8, 20). The sexual reproduction of the colonies of the Volvocaceae is one of the most important phenomena presented by the Protozoa. In some families of Flagellata full-grown individuals become amoeboid, fuse, encyst, and then break up into flagellate spores which develop simply to the parental form (fig. I, 23 to 26). In the Chlamydomonadidae a single adult individual by division produces small individuals, so-called ' microgametes." These conjugate with one another or with similar microgametes formed by other adults (as in Chlorogonium, fig.

1, 7); or more rarely in certain genera a microgamete conjugates with an ordinary individual megagamete. The result in either See also:

case is a " zygote," a cell formed by fusion of two which divides in the usual way to produce new individuals. The micro-gamete in this case is the male See also:element and See also:equivalent to a spermatozoon; the megagamete is the female and equivalent to an egg-cell. The zygote is a " fertilized egg," or oosperm. In some colony-See also:building forms we find that only certain cells produce by division microgametes; and, regarding the colony as a multicellular individual, we may consider these cells as testis-cells and their micro-gametes as spermatozoa. See also:CYSTOFLAGELLATA(RHYNCHOFLAGELLATAOf E.R.Lankester)and See also:DINOFLAGELLATA are scarcely more than subdivisions of Flagellata; but, following O. Butschli, we describe them separately; the three See also:groups being united into his See also:MASTIGOPHORA. Further Remarks on the Flagellates.—Besides the See also:work of See also:special Protozoologists, such as F. Cienkowski, O. Butschli, F. v. Stein, F. Schaudinn, W.

Saville Kent, &c., the Flagellates have been a favourite study with botanists, especially algologists: we may cite N. See also:

Pringsheim, F. Cohn, W. C. See also:Williamson, W. Zopf, P. A. Dangeard, G. Klebs, G. Senn, F. Schutt; the See also:reason for this is obvious. They present a wide range of structure, from the simple amoeboid genera to the highly differentiated cells of Euglenaceae, and the complex colonies of Proterospongia and Volvox.

By some they are regarded as the See also:

parent-group of the whole of the Protozoa—a position which may perhaps better be assigned to the Proteomyxa; but they seem undoubtedly ancestral to Dinoflagellates and to Cystoflagellates, as well as to See also:Sporozoa, and presumably to See also:Infusoria. Moreover, the only distinction between the Chlamydomonadidae and the true green Algae or Chlorophyceae is that when the former See also:divide in the resting condition, or are held together by gelatinization of the older cell-walls (See also:Palmella state), they round off and See also:separate, while the latter divide by a " party wall ' so as to give rise either to a cylindrical filament when the partitions are parallel and the axis of growth See also:constant (Conferva type), or to a plate of See also:tissue when the directions alternate in a plane. The same holds See also:good for the Chrysomonadaceae and Cryptomonadaceae, so that these little groups are included in all See also:text-books of See also:botany. Again among See also:Fungi, the zoospores of the Zoosporous Phycomycetes (Chytrydiaceae, Peronosporaceae, Saprolegniaceae) have the characters of the Bodonidae. Thus in two directions the Flagellates See also:lead up to undoubted See also:Plants. Probably also the Chlamydomonads have an ancestral relation to the Conjugatae in the widest sense, and the Chrysomonadaceae to the See also:Diatomaceae; both groups of obscure See also:affinity, since even the reproductive bodies have no special See also:organs of locomotion. For these reasons the Volvocaceae, Chloromonadaceae, Chrysomonadaceae and Cryptomonadaceae have been united as Phytoflagellates; and the Euglenaceae might well be added to these. It is easy to under-stand the relation of the saprophytic and the holophytic Flagellates to true plants. The capacity to absorb nutritive matter in See also:solution (as contrasted with the ingestion of solid matter) renders the encysted condition compatible with active growth, and what in holozoic forms is a true hypnocyst, a state in which all functions are put to See also:sleep, is here only a See also:rest from active locomotion, nutrition being only limited by the See also:supply of nutritive matter from without, and—in the case of holophytic species—by the See also:illumination: this latter condition naturally limits the possible growth in thickness in holophytes with undifferentiated tissues. The same considerations apply indeed to the larger parasitic organisms among Sporozoa, such as See also:Gregarines and Myxosporidia and Dolichosporidia, which are giants among Protozoa.

End of Article: FJG

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