LIST OF IRISH TESTACEA. 



507 



jiute, concentric, undulated striae ; the lateral 

 more regular, and diverging from the apex to 

 the base, and can only be distinctly seen by 

 means of a strong lens : umbo rather small, 

 and placed considerably to one side : hinge 

 with two central teeth and one lateral one in 

 each valve ; in the left valve is a large, broad, 

 bifid, reflected, elevated tooth, which bends 

 outwards, pointing to the umbo, two-thirds 

 of which rises above the margin of the shell ; 

 the other tooth is very thin, and runs ob- 

 liquely alongside the lateral tooth, which 

 rises aft tlie apex, and obliques towards the 

 anterior slope, over which is placed the liga- 

 ment : in the right valve one tooth is ob- 

 long, with a spoon-like cavity in its centre ; 

 the smaller tooth similar to that in the oppo- 

 site valve, but somewhat stronger and ob- 

 tuse; the lateral tooth the same as in the 

 left valve : inside of a yellowish- white, with 

 numerous glassy circular spots, and a very 

 large muscular impression, extending from 

 the margin (which is plain and glossy) two- 

 thirds across the shell : anterior slope much 

 produced ; posterior slope rounded. On the 

 outside, a subulate depression runs from the 

 apex to the base, in an oblique direction, 

 near the anterior slope. Length one inch ; 

 breadth one inch and three-eighths. 

 A complete shell and odd valve, were found by 

 Miss Hutchins in Bantry Bay, and are now 

 in the cabinet of Dr Taylor of Dublin. 



4, depressa. Donovan, Brit. Shells, t. 163. — Wood, Gen. 



Con. 171. t. 45. f. S. Dublin Bay, and Port- 

 marnock ; not uncommon. 



5. Fabula. Donovan, Brit. Shells, t. 97.— -Wood; Gen. Con. 



K k 4 



