*250 PNEUMONOBRANCHIATA. 



a sinus on the front edge, most probably caused by 

 the animal having lived on a stone which had a pro- 

 minence, under the name oiAncylus sinuosus. (Compl. 

 90. t. 16. f. 1,2.) 



Velletia. (Lake Limpet.) 

 The animal like Ancylus, but dextral ; the shell 

 oblong, compressed, conical, with the apex rather 

 behind the middle, bent to the left, as in other 

 dextral shells ; mouth elongate. 



97.2. Velletia lacustris. Oblong Lake Limpet, (t. 

 10. f. 126.) Shell oblong, compressed, with the 

 point slightly recurved in an oblique direction 

 and nearly central. 

 Ancylus lacustris. Miiller, Verm. ii. 199.; Drap. 

 p. 47. t. 2. f. 25—27.; Sowerby, Gen. f. 2.; Turton, 

 Man. ed. 1. 141. f. 126. 

 Patella lacustris. Montagu, p. 484.; Don, B. S. 



t.150. 

 Patella oblonga. Lightfoot, Phil. Trans, lxxvi. 



168. t. 2. f. 1. 5. ; Turt. Diet. p. 138. 

 Crepidula oblonga. Fleming, Ency. 

 In still waters, attached to aquatic plants. 

 Animal blackish. 



Shell a quarter of an inch long, and hardly a tenth 

 in breadth, extremely thin and transparent, smooth, 

 oblong, compressed at the sides, with the apex pointed 

 and near the centre of the shell, inclining towards 

 the narrower end, and turning a little obliquely to- 

 wards the left side.* 



* Mr. Guilding (Zool. Journ. iii. 535.) has described two 

 West Indian species of this genus, which I have lately had the 

 opportunity of re-examining and proving to be true Velletice, 

 which was doubtful from Mr. Guilding's erroneous description 

 of the animal. 



