274 Transactions of the Society. 



VII. — On Some Bhizopods from the Sikkim Himalaya. 

 By Eugene Penakd, Docteur es-sciences (Geneve). 



(^Read Febriiary 20, 1907.) 

 Plate XIV. 



Bulinella indica g. et sp. n. 



This rhizopod, which Mr. James Murray found in several 

 samples of Himalayan moss, sent to him by Mr. N. D. F. Pearce, 

 of Cambridge, and which he submitted to me for study, seemed to 

 me at first to belong to the genus Centropy,ds, but in reality it 

 differs from that genvis in some important characters. 



In Centropyxis the shell consists primarily of a chitinoid 

 membrane, punctate over its whole surface with a multitude of 

 little pomts, usually very obscure, and distantly recalling the 

 characteristic structure of the genus Arcella, and to this mem- 

 brane there adhere particles of extraneous matter, more or less 

 numerous. 



In Bulinella it is the extraneous matter, in the form of thin 

 silicious plates, which forms the shell itself, joined together by a 

 chitinous cement, more or less abundant. Moreover, the buccal 

 opening is not, as in Centropyxis, a more or less rounded depression, 

 invaginate or tubular, but a slit, long and very narrow, the plane 

 of opening of which is tangential to the surface of the shell. Two 

 lips can be distinguished, of which the lower, so to speak, passes 

 under the upper, producing an appearance which recalls that of 

 certain molluscs, such as Bidla, hence the name Bulinella applied 

 to the new genus. 



In Bulinella indica, which will be the type of the genus, the 

 shell, measuring 160-200/i in greatest diameter (which is its 

 width, as indicated by the position of the mouth), is arcelloid in 



EXPLANATION OF PLATE XIV. 



Fig. 1. — Bulinella indica, ventral face. 



,, 2. — Diagrammatic section, antero-posterior. 



,, 3. — Contour of the lips, seen from above. The thick line 

 indicates the upper lip, the thin line the lower lip. 



,, 4. — Broken fragment of a shell, from the buccal region. 

 The arched lower lip is seen with its anterior 

 thickening, and a part of the upper lip, with several 

 pores, the fracture passing through two of these. 



