GENUS COCnLlOPODIUM— COCHLIOPODIUM BILIMP.OSUM. 187 



The sarcode of Cochliopodmm is so closely adherent to the flexible 

 and elastic investing shell that in all its changes of form, the shell accommo- 

 dates itself to those changes. It consists of a pale, finely granular proto- 

 plasm, having scattered through the mass variable proportions of clear and 

 darkly outlined round and oval corpuscles, which have an oleaginous or a 

 starch-like appearance. Mingled with these there are commonly a few 

 liquid globules or vacuoles, of which one or two may from time to time be 

 recognized as contractile vesicles. Among the coarser elements of the 

 sarcode, crystals are often present. The usual food contents consist of 

 diatoms and one-celled alga?, together with some sand grains. 



A large round nucleus with a large pale granular nucleolus occupies 

 the sarcode toward the fundus of the shell. 



The more conspicuously granular portion of the sarcode ordinarily 

 remains confined within the thicker portion of the shell, while only a clearer 

 portion spreads outwardly within the thin basal band of the shell. 



The pseudopods of Cochliopodium are usually seen as hyaline awl- 

 shaped extensions of the sarcode, of variable proportions, generally simple, 

 but not unfrequently forking or moderately branching at the end. They 

 often appear as delicate conical or more acuminate extensions from beneath 

 the expanded border of the shell, and look as if they were actually processes 

 of the latter. They also appear as more granular or darker extensions 

 from the chief mass of the sarcode, seen through the basal band of the 

 shell and projecting beyond it, as represented in figs. 5, 7, 15-17, 21-23. 



Individuals are frequently observed in which the pseudopodal exten- 

 sions seem to perforate the shell, as represented in figs. 10, 12. Auerbach, 

 in describing the animal as Amoeba hilimbosa, supposed that it actually had 

 the power of forcing its pseudopods through the investing membrane; and 

 this view appears to have been held by Greeff and Archer in Amphizonella. 

 Hertwig and Lesser, and afterward Schulze, explained the true nature of 

 this appearance, which seems to be due to the pseudopodal extensions pro- 

 truding from between narrow folds of the bottom of the investing shell. 



Cochliopodium bilimbosum is commonly observed gliding slowly over 

 the surface of objects, as a round or oval granular body, included by a 

 delicate zone or crescentic band of variable extent. The body is often so 

 minute and transparent as readily to escape notice. The zone or band is 

 of such extreme transparency and tenuity as scarcely to be visible with- 



