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Radiolaria (Haeckel). The delimitation of Sarcodina is not unattended with difficulties. A very few of those we include possess in addition to the pseudo-pods one or more flagella, such as Dimorpha and Myriophrys (Heliozoa), Arcuothrix (Rhizopoda), and might equally be referred to the See also:

FLAGELLATA

Flagellata (q.v.). The See also:

SPOROZOA

Sporozoa differ in that their active See also:

state is usually (not always, e.g. See also:

HAEMOSPORIDIA

Haemosporidia, &c.) a wriggling, sickle-shaped See also:

CELL (from Lat. cella, probably from an Indo-European kal —seen in Lat. celare, to hide; another suggestion connects the word with Lat. cera, wax, taking the original meaning to refer to the honeycomb)

cell, that growth takes See also:

PLACE (through Fr. from Lat. platea, street; Gr. IrAar6s, wide)

place in the whole See also:

SURFACE

surface of the body, and not by ingestion of See also:

food and consequently without the active deformations that characterize Sarcodina, and that the See also:

LIFE

life-See also:

cycle embraces at least two alternating modes of brood formation. The subdivision of the phylum is no less difficult. The See also:

CHARACTER (Gr. xapareri7p, from xap&crew, to scratch)

character of the pseudopods (see See also:

AMOEBA

AMOEBA) is the most obvious one to select, as it appears to be fairly See also:

CONSTANT, BENJAMIN (1845-1902)

constant. The surface may be a " precipitation-pellicle," not wetted by See also:

WATER

water, and the cytoplasm immediately within (" ectosarc ") See also:

FREE

free from granules, so that no streaming See also:

MOVEMENT

movement is visible at the surface of the pseudopods, which are See also:

blunt or See also:

TAPER (probably of Celtic origin, cf. Irish tapar, Welsh tampr, taper, torch)

taper sharply to a point (Rhizopoda Lobosa); or the cytoplasm has no such protective See also:

OUTER

outer layer, and the granules extend to the surface where they show a constant streaming, and the pseudopods are See also:

FINE

fine-pointed, and taper very slowly to the tip, as in all the other See also:

groups. For convenience, however, from See also:

general similarity of See also:

HABIT (through the French from Lat. habitus, from habere, to have, hold, or, in a reflective sense, to be in a certain condition; in many of the English senses the French use habitude, not habit)

habit, See also:

HABITAT (a French word derived from habiter, Lat. habitare, to dwell)

habitat and general structure, we have been obliged to give a See also:

minor importance to this character within Rhizopoda. The divisions then stand thus: I.

PROTEOMYXA.—Pseudopods fine granular, not branching freely; fission usually multiple, in a cyst; no conjugation See also:

PROCESS

process known. 2. RHIZOPODA.—Simple forms, sometimes with a simple See also:

shell, chitinous, siliceous or of cemented particles, never calcareous; pseudopods lobose, in the tapering and branching never either stiff or reticulate. 3. HELIOzoA.—Pseudopods granular, finely radiate, and gradually tapering, stiff ; See also:

SKELETON

skeleton variable, never calcareous nor of cemented particles. 4. FoRAMINIFERA.—Pseudopods branching freely and anastomosing, flexible except in a few pelagic forms where they are more radiate; shell variable, mostly of cemented See also:

sand-grains, calcareous, very rarely siliceous in a few deep-See also:

sea forms, not generically separable from 5. RADIOLARIA.—Cytoplasm divided into a central and a peripheral region by a perforated membranous central See also:

CAPSULE (from the Lat. capsula, a small box)

capsule; pseudo-pods radiate flexible branching or not; skeleton either of a proteid (?) substance (" a canthin ") or siliceous, of spicules or forming an elegant lattice, more rarely continuous. 6. See also:

LABYRINTHULIDEA

LABYRINTHULIDEA.--Body a reticulate plasmodium, formed by cells more or less coalescent, and connected by a network of anastomosing threadlike pseudopods. Cells aggregated into loose networks without distinct boundaries, the minor aggregates connected by fine threadlike pseudopodia. 7.

MYxOMYCETES.—Cells at first free, finally aggregated to See also:

FORM (Lat. forma)

form a coalescent fructification, usually preceded by a continuous or fenestrated plasmodium See also:

STAGE (Fr. 6/age; from Lat. stare, to stand)

stage in which all cytoplasmic boundaries may be lost. The See also:

REPRODUCTION

reproduction processes of the Sarcodina are (I) Binary fission, equal or nearly so. (2) Multiple fission or " sporulation " (also termed " brood formation "). Conjugation (equal or unequal) usually occurs between cells produced by the latter mode (microgametes) ; or if not, there are antecedent processes suggesting that brood formation has been lost. Conjugation is entirely unknown in Proteomyxa, Labyrinthulidea and Myxomycetes, even at stages where it occurs in other groups, and it has only been definitely made out in a very limited number of genera in the remaining groups. The zygote or product of cell See also:

FUSION

fusion is usually here, as in the See also:

MAJORITY (Fr. majorite; Med. Lat. majoritas; Lat. major, greater)

majority of types of conjugation, a resting cell. (See the See also:

SEPARATE

separate articles on the classes.) The See also:

young of the Sarcodina, formed from' the outcome of multiple fission, or single resting cells (spores), may be provided with pseudopodia from the first (myxopods or amoebulae), or come into active life for a See also:

SHORT, FRANCIS JOB (1857– )

short See also:

time with flagella (mastigopods or flagellulae). (M.

End of Article: SARCODINA

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