338 Mr. A. Hancock on some new species of Shells. 



Lyonsia gibbosa, mihi. PI. V. fig. 11, 12. 

 Anatina striata, Gray, App. Ross's Voy. 



Shell ventricose, oblong-ovate, thin, dull, opake white, slightly 

 wrinkled concentrically and striated longitudinally, with a deli- 

 cate olivaceous epidermis ; umbones large, tumid, placed a little 

 towards the anterior end, which has the dorsal margin concave, 

 with a rather deep ovate depression immediately under the beaks ; 

 the posterior dorsal margin straight, with the end a little twisted, 

 slightly gaping and obliquely truncated ; from thence the ventral 

 margin is arched pretty regularly to the anterior end, which is 

 well rounded ; interior white, approaching to a pearly lustre ; os- 

 siculum triangular, with the posterior end concave. Length up- 

 wards of 1 inch ; breadth f inch ; depth \ inch. 



Mr. Gray informs me that this is his Anatina striata, but I 

 have not been able to find the original description. 



The Mya striata of Montagu, to which probably Mr. Gray re- 

 ferred his shell, is certainly distinct from the specimens brought 

 by Messrs. Warham and Harrison. The dull opake white colour 

 devoid of nacreous lustre, the tumid beaks and the concavity of 

 the margin in front of them, with the ovate depression, are suffi- 

 cient to distinguish it. 



The Mya striata of Montagu, however, is most likely a variety 

 of L. norvegica, as considered by Turton ; but whether so or not, 

 Mr. Gray's name having been used cannot be retained. 



This species differs from L. norvegica by its whiteness, opacity 

 and want of nacreous lustre ; it is not so broad, is more gibbous, 

 and has the beaks larger and more tumid ; the posterior end is 

 not so much produced, is less squarely truncated, and the lon- 

 gitudinal striae are stronger and further apart. 



EXPLANATION OF PLATE V. 



Figs. 1, 2. Different views of Buccinum tenebrosum. 



Fig. 3. Fusus pellucidus. 



Figs. 4, 5. Different views of Margarita Harrisoni. 



Fig. 6. Buccinum sericatum. 



Fig. 7. Buccinum hydrophanum. 



Figs. 8, 9. Different views of Buccinum Grcenlandicum. 



Fig. 10. Fusus Sabini. 



Figs. 11, 12. Different views of Lyonsia gibbosa. 



Figs. 13, 14. Different views of Nucula inftata. 



Figs. 15, 16. Different views of Astarte Warhami. 



