CDS 



Transactions of the Society, 



X — Notices of New Infusoria Flag ellata from American Fresh 



Waters. 



By Alfred C. Stokes, M.D. 



{Read 9th May, 1888.) 



Plate XI. 



Mastigamoeba flexuosa, sp. nov. Fig. 1. 



Extended body elongate-ovate or sublinear, from five to six times as 

 long as broad ; the anterior extremity obtusely pointed ; pseudopodia 

 numerous, their length equalling or exceeding the breadth of the body, 

 smooth, tapering, seldom branching, those of the posterior extremity 

 similar to the lateral ones, or fine, filamentous and short, or both ; 

 the posterior border also often emitting a broad, irregular, -wave-like 

 pseudopodium ; anterior extremity usually exhibiting a lateral, ante- 

 riorly directed pseudopodium on each side of the flagelliferous apex ; 

 endoplasm of the pseudopodia containing many short, fine, colourless, 

 rod-like stnictures; endoplasm of the body coarsely granular, fre- 

 quently inclosing numerous greenish-yellow food-masses, the granules 

 entering the pseudopodic extensions for only a short distance ; flagellum 

 about one-half the length of the body ; contractile vesicle apparently 

 single, near the posterior extremity ; nucleus (?) subpyriform, close to 

 the anterior extremity. Length of body 1/150 in. Habitat: Pond 

 water. 



The movements are slow so far as progression is concerned, but 

 quite active in connection with change of form, the soft body bending 

 on itself, shortening, lengthening, and undergoing various other 

 changes of shape with considerable rapidity. Excrementitious par- 

 ticles are extruded with some force, apparently from any portion of 

 the surface. 



Cercomonas fruncata, sp. nov. Figs. 2-6. 



Body ovate or elongate flask-shaped, soft, flexible and changeable 

 in form, especially posteriorly; length from two to four times the 

 breadth ; dorsal surface rounded, the ventral flattened, sometimes 

 slightly concave; posterior extremity usually rounded, the anterior 

 narrow and truncate ; posterior appendage trailing, stout, exceeding 

 the body in length, largest near the body, tapering and changeable in 



EXPLANATION OF PLATE XI. 



Fig. 1. — Mastigamaha flexuosa. 



„ 2-6. — Cercomonas truncata. 



» 7. — „ heterofilum. 



)) 8. — „ lapsa. 



» 9- — ,, undulans. 



„ 10-12. „ niutabilis. 



„ 13. — Heteromita granuUfera. 



„ 14, 1."). „ tremula. 



.) 16. — „ stitgnatilis. 



K 17. — „ Sphayni. 



Fig. 18. — Heteromita nasttta. 



„ 19.— „ parvifilum. 



„ 20. — Tetramitus frondarius. 



■„ 21. — Hexamita truncata. 



„ 22. — Atractonema pitsilla. 



„ 23. — Hymenomonas flava. 



„ 24. — Hyinenornonas fusiformis, 



„ 25. — Zygoselmis dbovata. 



„ 26. — Sterromonas parvula. 



„ 27.— Anisonema M^ixm. 



