58 PULMONATA. 



head behind the lower tentacles. Aperture of generation at the 

 back of the right tentacle. " Teeth regular, numerous." 



Shell oblong, depressed, expanded, thin ; mouth very large ; 

 apex subspiral, thick, solid. 



Parmacella, sp., Webb Sf Van Beneden, Mag. Zool. 



Gray, Fig. Moll, iv., in Mrs. Gray's Fig. Moll. t. 282. f. 2. 



Messrs. Webb and Van Beneden do not mention the caudal 

 gland in their description, but it is very visible in Morelefs 

 figure and the one figured by Ferussac. 



1. Drusia Valenciennii. 



Shell depressed, oblong, spathulate, concentrically striated ; 

 apex pale green, thick, smooth, of half a whorl. 



Parmacella Valenciennii, Webb S)- Van Beneden, Mag. Zool. 

 Gray, Fig. Moll. iv. & iii. t. 282. f. 2. 

 Morelet, Moll. Portugal, 40. t. 4, from hfe. 



Hab. Portugal, in the Hippurite hills of Alcantara (Webb). 



Herbivorous, living chiefly on Cochlearia acaulis, breeding 

 ill April. 



" The shell is of an oblong spatulate shape, marked with striae 

 of growth ; it is very thin and extremely fragile, olive out- 

 side and pearly within. Its base terminates in an extremely 

 smooth demi-spire of a clear gi-een colour. On one of the sides 

 of the spire, between it and the margin of the plate of the 

 shell, there is a kind of small raised hook to which a protube- 

 rance of the skin correspoiuls on the back of the animal ; this 

 protuberance, when seized between the hook and the margin of 

 the shell, serves to fix this latter in its place ; so that if not at- 

 tended to, it is apt to be broken ofl", in attempting to raise it. 

 This circumstance does not exist in the Cryptella of the Canaries, 

 and we know not if it be found in other species of the genus 

 Parmacella. An appendage of the skin enters also the demi- 

 spire, of which it assumes the form." — D'ebb. 



" Jaws like a horse's hoof." — Morelet. 



" Mr. Webb's figure from the animal preserved in spirits is 

 detestable : the form, the develo])ment of the jaws, the contrac- 

 tion of the tentacles, give an entirely false idea of the animal." — 

 Morelet, 44. 



" Ce coquille proprement dite, qui fait saillee an ])oint ou le 

 tortillon se separe du plan locomoteur, est entierement re- 

 couverte ])ar la membrane fine et blanchatre qui tapisse la 

 crypte intermediaire. EUe engaine I'extremite de I'animal, qui 

 se termin(» comme celle des Helices. 



