92 PHYTOPHAGA. 



Young shell with numerous hairy bands : 

 Helix compactilis. Pulteney. 

 Very young shell. 

 Vitrina femorata. Anctor. 



Inhab. rivers. 



Shell resembling the last, but of a more oblong 

 shape, with six volutions, which are not so much 

 swollen, and consequently the sutures are not so deep. 

 The young shells are furnished with numerous close 

 ciliated spiral lines. Lister gives the anatomy of the 

 former species, and Cuvier of this (t. 6. f. 1. 4.), in the 

 Mem. Mollusques. 



Though Lister has figured the two species as found 

 in Britain, they had been confounded by English 

 conchologists until I noticed them in the Medical 

 Repository for 1821, when I also pointed out that they 

 were known to Lister, and that the young shell of the 

 two species offered the very different characters noticed 

 in their descriptions. They are sometimes found to- 

 gether in the same river, as at Uxbridge, Middlesex. 



Miiller, in his figures of this animal, in the Zoobgia 

 Danica, represents two small processes at the hinder 

 part of the opercular mantle, as in the animal of 

 Lacuna. Can he have represented a specimen of that 

 genus, by mistake, for he has figured the animal as 

 red? 



4.2. Bithinia Gray. (Bithinia.) 



Operculum lined internally with a thick shelly coat ; 

 nucleus subcentral (p. 78. f. 11.) ; the mouth of the 

 shell ovate, continued, rather angular behind, with a 

 slightly thickened internal rib. (See p. 78. f. 9, 10.) 



