. Fresh-water biology. Freshwater biology. 232 FRESH-WATER BIOLOGY (142) 142 (141) Plates distinct, large size. Trinema enchelys Ehrenberg 1836. The aperture is circular in this species and surrounded by a num- ber of rows of very minute chitiaous plates. Pseudopodia very fine and long, usually few in number. This is the most common species of the genus and is found everywhere among mosses. Length 40 to 100 li. Fig. 342. Trinema enchelys. X 310. (After Penard.) Plates indistinct, small size. Trinema lineare Penard i8go. The plates of this small form are indistinct except about the edges, where
. Fresh-water biology. Freshwater biology. 232 FRESH-WATER BIOLOGY (142) 142 (141) Plates distinct, large size. Trinema enchelys Ehrenberg 1836. The aperture is circular in this species and surrounded by a num- ber of rows of very minute chitiaous plates. Pseudopodia very fine and long, usually few in number. This is the most common species of the genus and is found everywhere among mosses. Length 40 to 100 li. Fig. 342. Trinema enchelys. X 310. (After Penard.) Plates indistinct, small size. Trinema lineare Penard i8go. The plates of this small form are indistinct except about the edges, where they may appear as minute undulations. The aperture is round. Habitat as other species. Length 16 to 26 fi. Fig. 343. Trinema lineare. X 500. (After Penard.) 143 (138) Shell shaped as Trinema; aperture subterminal; plates elongate. Corythion Taranek. Representative species. . Corythion dubium Taranek 1882. In this species the shape of the aperture is characteristic, its border rep- resenting two unequal arcs placed together, the anterior one the longer. The plates are close together but not overlapping. Habitat mosses. Length 35 to 40 m. Fig. 344. Corythion dubium. X 37s. (After Penard.) 144(2) Pseudopodia usually anastomosing. . 145 145 (158) Pseudopodia very delicate, usually finely branched. Subclass Forammifera . 146 146 (147) Body without a covering; pseudopodia formed from any part of the surface. , Biomyxa Leidy. Representative species. . Biomyxa vagans Leidy 1875. The body moves slowly but continuously, no distinction between ectoplasm and endoplasm being observed. Pseu- dopodia long, branching and anastomosing, always chang- ing. A granular nucleus and a number of contractile vacuoles are present. Habitat sphagnous swamps. Large individuals may measure 480 il between the tips of the pseudopodia. Fig. 345. Biomyxa vagans. X 65. (After Penard.) 147 (146) Body with a distinct covering. .... . 148 148 (153) Pseudopodia extending from more than one aperture. . 149 149(152)
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