189 



9. AZECA Leach. (Trident Shell.) 



Animal like Bulimus, with subcylindrical, rather 

 obtuse shell, covered with a polished periostraca ; 

 aperture pear-shaped, curved and pointed at the 

 top ; the margin thick, obtuse, and united all round 

 and toothed ; the axis imperforated. 



In shape, colour, polish and habitat, this shell so 

 exactly resembles the Bulimus lubricus, that some 

 have questioned if this latter shell be not the same in 

 its earlier stage of formation before the teeth appear ; 

 but the singular shape of the aperture decidedly re- 

 moves it into a distinct genus, which is adopted from 

 Dr. Leach. 



Mr. Alder considers this genus as intermediate 

 between Bulimus and Clausilia, resembling the former 

 in shape, and approaching more to the latter in having 

 the peris tome complete, and also more particularly in 

 having a longitudinal plate on the columella, consi- 

 derably within the aperture, similar in situation and 

 making a slight approach in form to the Clausium 

 of the genus Clausilia, though attached through its 

 whole length, and inflexible. 



63. 1. AZECA tridens. Glossy Trident Shell, (t. 5. 



f. 52.) 

 Turbo tridens. Montagu, p. 338. t. 11. f. 2.; 



Laskey, Warn. Soc. i. p. 406. t. 8. f. 11. 

 Pupa Goodalli. Ferussac, Prod. 71. 



Britannica. Kenyon, Mag. N. H. ii. 426. f. n. 



Azeca tridens. Leach, Moll. p. 1*22. t. 8. f. 8.; 



Alder, Cat. 32. 



