Acellina.'] inffsokiat, ANiMAtCFLKS. 215 



Genus Ctptioderia. — Lorica membranous, resistant, ovoid elon- 

 gated anteriorly, where it is ciu'ved, and constricted in the form of a 

 neck ; surface marked by prominent points in oblique rows ; aperture 

 circular, obliqiie, expansions very long, filiform, very fine at the 

 extremity, and simple or branching. 



The oblique disposition of the rows of points, the obliquity of the 

 aperture, and the character of the expansions, bring this genus into 

 affinity with Trinema (Duj.); but the interior constriction, forming 

 a neck, seems sufficiently distinctive between the two. 



C. margaritacea. — Lorica yellow; the translucent points looking 

 like rows of pearls. Processes attain twice the length of the shell. 

 Length l-395th. Breadth l-840th to l-408th. Common in the 

 water of the Vosgcs with vegetable debris. The fonn of the lorica 

 varies ; at one time the neck may be but rudimentaiy ; at another 

 the posterior end, instead of being wide and roimdcd, is conti'acted 

 suddenly to a truncated apex. 



Genus PsEUDO-DiFFLiTGiA. — Shell membranous, ovoid, or ovo- 

 globular, smooth or striped spirally, with a wide round opening, 

 whence proceed numerous long, slender expansions, either simple or 

 branching. 



This genus is allied to Bifflugia by the form and character of its 

 shell, but differs from it in the nature of the expansions. 



P. gracilis. — Shell blueish brown, brittle ; surface, as if beset with 

 minute grains of sand, of a more or less elongated ovoid figure, ex- 

 pansions filiform, very long. Length 1- 740th to l-465th. Breadth 

 1 -890th to 1 -740th. Found near Mulhouse. 



Genus Sphenodeeia. — Shell diaphanous, coloiirless, resistant glo- 

 bular, with a flattened wedge-shaped neck, surface marked by 

 polygonal depressions, disposed in regular oblique rows ; aperture 

 terminal, compressed, almost linear. Expansions filiform, very long 

 and attenuated. 



The form of the aperiiu'e and of the neck separate this genus from 

 Trinema and Eiiglypha, to which it is allied by the sti-ucture of its 

 lorica. 



S. lenta. — Lorica as above described, expansions few, veiy long, 

 slender, and simple, or branching. Length 1 -650th to 1 -520th. 

 " Of aU the Rhizopodes (says Dujardin) this is the slowest in its 



