230 FEESH-WATEE BHIZOPODS OF NOBTH AMEEICA. 



Sphenoderia lenta is the subject of one of the descriptions of certain 

 species and genera of Bbizopods, by Schlumberger, in the 'Annales des 

 Sciences Naturelles' for 1845. The descriptions, beiug brief and unac- 

 companied by illustrations, have given rise to differences of opinion as to 

 what particular forms they apply. The genus Sphenoderia is described as 

 possessing- "a diaphanous, globular shell, ornamented with polygonal im- 

 pressions in regular oblique series, and having a broad, and short wedge- 

 shaped neck, with the terminal aperture almost linear." The pseudopods 

 are filiform, long and fine. The form of the neck and of the aperture 

 separates the genus from Trinema and Euglypba, to which it is related in 

 the structure of the shell. 



Later, Mr. Carter described a rhizopod, under the name of Eughjplia 

 qlobosa, with a globular shell having a short, compressed, wedge-shaped 

 neck, which has appeared to me to be the same thing. Schulze remarks that 

 the Euglyplia globosa is probably the same as Sphenoderia, but considers it 

 uncertain for want of figures of the latter for comparison.* 



Sphenoderia leiafa, which I regard the same as Euglyplia globosa, 

 is common in the wet sphagnum of sphagnous swamps, and is also less 

 frequently to be found about the roots of Selaginella, Hypnum, and other 

 mosses and plants in bogs. 



It is a comparatively minute creature, like Trinema, and is also a shy 

 animal, little disposed to movement when disturbed. 



The shell has the form of an oval or spherical sac, or less frequently 

 is oblong oval, and is provided with a short neck. The body is usually of 

 uniform transverse diameter, but is sometimes more or less compressed. 

 The fundus is obtusely rounded and devoid of appendages. See figs. 25- 

 41, pi. XXXIV. 



Like other investigators, I have been puzzled to ascertain the exact char- 

 acters of the neck and mouth of the shell. In the ordinary view, the neck 

 has appeared to me to be short, wide, and saucer-shaped, with an elliptical 

 mouth. In the opposite direction it appears as a conical point, whence no 

 doubt the name of the genus Sphenoderia, signifying wedge-like neck. In 

 viewing the shell in an intermediate position, by causing it to turn on its 

 axis, the neck appeai-s as a pair of conical points, with the border of the 

 mouth festooned between them. I have supposed the mouth to be elliptical 



* Arcliiv f. mikroskoi>isclie Anatomic, !«<">, 104. 



