Stokes.] dVO [So\. 5, 



Acineta lacustris, sp. nov. (Fig. 18). 



Lorica elongate-obovate or subvasiform, strongly compressed, less than 

 three times as long as broad, widest anteriorly, the sides continuous across 

 the frontal border, leaving a rounded lateral aperture at each angle (or the 

 exit of the tentacles ; slightly constricted beneath the anterior border, and 

 very moderately inflated near the posterior extremity, the frontal margin 

 concave; pedicel very short and hollow; enclosed zooid often entirely 

 filling the entire cavity of the lorica ; tentacles in two antero-lateral fasci- 

 cles, distinctly capitate ; contractile vesicle single, placed near the anterior 

 border; nucleus elongate, vertical ; endoplasm granular. Length of the 

 lorica ^^ to T £ 7 inch. Habitat — Pond-water ; attached to Anacharis. 



Acineta stagnatilis, sp. nov. (Fig. 19). 



Lorica subcircular in outline, rounded and inflated posteriorly, com- 

 pressed anteriorly, the frontal border irregularly convex ; pedicel short, 

 hollow, from one- fourth to one-fifth as long as the lorica, widest at its 

 junction with the sheath, tapering thence and terminating in a button-like 

 point of attachment ; frontal margin pierced by a slit-like fissure, and two 

 anteriorly converging, narrow fissures on the front and rear walls, for the 

 exit of the tentacles ; the enclosed animalcule occupying the centre of the 

 lorica, apparently not attached to the walls, subspheroidal, the anterior 

 border truncate ; tentacles more or less fascicled, capitate ; contractile vesi- 

 cle single, postero-lateral ; endoplasm granular. Length of the lorica, 

 including pedicel, T i 5 inch. Habitat — Pond-water ; on Myriophyllum. 



EXPLANATION OF THE FIGURES. 



Figs. 1-4. Mastigamceba longifilum ; different forms of one individual. 

 Fig. 5. Anisonema pusilla, X 900. 

 Fig. G. Trentonia flagellata, X 430 ; gen. et sp. nov. 

 Fig. 7. Cryptoglena truncata, X 772. 



Figs. 8, 9. Cyclonexis annularis, X 030 ; front and side views ; gen. et 

 sp. nov. 



Fig. 10. Pyxidium urceolatum, X 290. 



Fig. 11. Rhabdostyla invaginata, X 750. 



Figs. 12, 13. Opisthostyla annulata, X 730 ; gen. et sp. nov. 



Fig. 14. Colpoda depressa, X 300. 



Fig. 15. Metopides acuminata, X 375. 



Fig. 16. Trichophrya sinuosa, X 255. 



Fig. 17. Acinetactis mirabilis, X 900 ; gen. et sp. nov. 



Fig. 18. Acineta lacustris, X 415. 



Fig. 19. Acineta stagnatilis, X 135. 



