413 Dr. J. E. Gray on two new genera of Land Mollusca. 



XXXIX. — Descriptions of two new genera (Pfeifferia and Janella) 

 of Land Mollusca. By J. E. Gray, Ph.D., E.R.S., V.P.Z.S. 



Some years ago I described a new genus of Helices under the 

 name of Nanina, remarkable from the mantle of the animal being 

 reiiexed and produced over the surface of the shell, like Vitrina, 

 but difFeiing from that genus in the shell being more Helicoid, 

 and in the mantle not being produced in front, or forming a 

 kind of shield over the back of the neck ; this genus has been 

 very generally adopted, and now contains a large number of 

 species. 



The animal of Nanina, like the ParmaceUa> and Helicai-iones, 

 has the hinder part of the uppermost extremity of the foot 

 truncated and furnished with a linear perpendicular gland with 

 thickened lips. 



Mr. Cuming, who lately supplied me with a number of ani- 

 mals of shells in spirit, sent me, along with other kinds, spe- 

 cimens of a shell which Dr. PfeifFer has described under the 

 name of Helix micans, which at once attracted my attention, on 

 account of the shell near the peristome being covered with a 

 thin reflexed portion of the mantle. I at first considered it was 

 a modification of the genus Nanina with a more dilated mantle, 

 and a much more globular shell ; but on more particular exa- 

 mination, I am convinced that it is the type of a new genus, as 

 the back of the foot is depressed and flattened, and quite destitute 

 of any appearance of a subcaudal gland. 



I propose to call this genus Pfeifferia, after my excellent 

 friend Dr. Louis Pfeiffer, the author of the " Monographia He- 

 licum," and it may be characterized as follows : — 



Pfeifferia. 



Animal large for the size of the shell ; mantle edge expanded, 

 thin, reflexed over the outer surface of the shell when contracted 

 in spirits, forming an even margin to the outer part of the 

 peristome. Foot moderate, depressed behind, acute at the tips, 

 without any subcaudal gland. Shell subglobose, imperforate, 

 thin, brittle, white, pellucid. Spire with small whorls, third and 

 fourth rapidly enlarging, the last inflated; aperture rounded, 

 lunate. Columella slightly and regularly arched. The peristome 

 thin, straight, acute. 



Mr. Cuming informs me, that when he poured boiling water 

 on them, to kill the animal, the animal, in attempting to return 

 within the shell, burst it, from being so much larger than the shell 

 itself; in consequence he was compelled to drown the animal and 

 let it remain in the water until it was half putrid, by which means 



