236 PNEUMONOBRANCHIATA. 



Rossmasler [Icon. i. 98.) thinks that Dr. Turton's 

 figure (f. 101.) represents what he considers a species 

 under the name of Limnceus vulgaris, which is not the 

 L. vulgaris of Jeffreys. 



Mr. Jeffreys says, " The young shells of L. acutus are 

 of a more elongated form than those of either L. auri- 

 cularius or L. pereger. It has a more oblique and less 

 ampullaceous form, and is of a thicker consistency, 

 than L. auricular ius." Mr. Alder regards this variety 

 as intermediate between L. pereger and L. auricu- 

 larius, and says, that if it is not a distinct species, it 

 may lead us to unite them all into one. It comes 

 very near L. lineatus of Mr. Bean. The single speci- 

 men we have in the British Museum, from Mr. Alder, 

 leads me here to consider it only a variety of L. pereger, 

 as it much resembles a common London variety of that 

 shell ; and I still think L. auricularius is a species. 



The Gulnaria lacustris of Leach is very peculiar, 

 from the erosion of its tips, probably arising from its 

 locality, the lakes of Cumberland. We have very 

 similar, but rather darker and thicker shells, with 

 lips perfect, from Lough Neagh, Ireland. 



The latter variety may prove a distinct species, 

 when we shall have received more specimens and are 

 able to observe the animal. 



90. 3. Limnceus stagnalis. Lake Mud Shell, (t. 7. 

 f. 104.) Shell oval, subulate, pointed, brittle ; 

 spire acute ; whorls five ; lower volution much 

 inflated, and somewhat angular ; the suture 

 deep. 



f. 38, 39. ; 

 1. 121. f. 



