14 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



26. Shell delicate ; body with a granular central zone ; 



individuals united by the pseudopodia Platoum 



Shell delicate ; body without central zone ; with a 

 short neck and a lateral mouth Microgromia* 



27. Shell of sand grains Amphitrema 



Shell without sand grains 28 



28. Shell delicate ; two lateral pseudopod openings ; with 



yellow to red oil drops Diplophrys* 



Shell chitinous : with two terminal pseudopod open- 

 ings . Ditrema 



Shell chitinous, spherical ; with many pore-like open- 

 ings Microcometes 



Description of Genera. 



Hyalodiscus H. & L. 



Round to elongated disk-shaped ; without evident 

 pseudopodia ; moving without much change in shape. 

 Nucleus and contractile vacuole always present. 

 Hy. Umax Duj., Figs. 2, 8. 

 Hy. gnttula Duj., Figs. 3, 4. 

 Amoeba Ehrbg. 



Usually a sharp differentiation of ectoplasm and ento- 

 plasm. One large nucleus or many small nuclei present, 

 and also one or more contractile vacuoles. Pseudopodia 

 generally lobe-like, seldom branched. Reproduction by 

 division in motile stage. 

 Am. protens Leidy, Fig. i. 

 Am. verrucosa Ehrbg., Figs. 5 and 6. 

 Pelomyxa Greeff. 



With broad, sack-like pseudopodia; ectosarc apparent 

 only in places ; hyaline ; entosarc vacuolated. Nuclei 

 numerous. With fine hyaline rods, which often form a 

 covering over the body. 



Fig. 7 is, with some doubt, referred to this genus, its 

 small size rendering its identification uncertain. It is, per- 

 haps, only a species of Hyalodiscus. 

 Dactylosphaerium H. & L. 



Body round ; pseudopodia ray-like, arising from all 

 sides of the disk-formed body ; short lobe-like pseudopodia. 



