VELLETIA. 221 



In Velletia no part of the cross row of teeth is 

 straight ; its central part is much arched, and is com- 

 posed of the central tooth and twelve lateral teeth 

 on each side, which do not alter much in form ; then 

 comes one tooth of a different form, and lastly six 

 more on each side, which latter are in a slight curve. 



99. 1. VELLETIA lacustris. Oblong Lake Limpet. 

 Shell oblong, compressed, with the point 

 slightly recurved in an oblique direction and 

 nearly central, (t. 10. f. 126.) 



Ancylus lacustris. Mutter, 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, T. B. p. 484. ; Don. 

 B. S. t. 150. (not Linn.} Patella oblonga. Lightfoot, 

 Phil. Trans. Ixxvi. (1786), 168. t. 2. f. 1. 5.; Turt. Diet. 

 p. 138. Crepidula oblonga. Fleming, Ency. Ancylus 

 oblongus. Forbes and Hanley, B. M. iv. 188. t. 122. f. 5. ; 

 Clark, Ann. and Mag. N. H. xv. 278. Patella cornea. 

 Poiret, Prod. Velletia lacustris. Gray, Man. 251. t. 10. 

 f. 126. Acroloxus lacustris. Beck, Ind. 124. Ancylus 

 Moquinianus. Bourg. Jour. Conch. 1853, 197. t. 6. f. 9. 



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, in- 

 clining towards the narrower end, and turning a 

 little obliquely towards the left side.* 



The egg cases are very depressed, orbicular or 



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

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

 opportunity of reexamining and proving to be true Velletia, 

 which was doubtful from Mr. Guilding's erroneous description 

 of the animal. 



