232 VENUS. 



wards the skies, especially the anterior side, into irregular 

 wart-like knobs ; these ridges have generally: their outer- 

 surface and the interstices transversely striate, and tqwards 

 the hinge the spaces between the ridges are striate. longi- 

 tudinally : beaks curving much to one side, with a broad 

 heart-shaped depression on the posterior slope j the ante- 

 rior slope of one valve turns suddenly in, and is finely striate 

 longitudinally, and marked with brown transverse streaks : 

 color dirty white, more or less tinged with rufous-brown ; 

 inside smooth, white, with the margin finely notched : 

 length two inches and a half ; breadth rather more. 



Young shells are flatter, much thinner, not much tuber- 

 cled, broader in proportion to the length, and the spaces 

 between them are entirely crossed by fine lines. A com- 

 parison of the young shell, or what has been called V. can- 

 cellata, with one of full growth, will instantly bring con- 

 viction of their identity, especially if one of intermediate 

 size be interposed. With the former, Mr. Dillvvyn has 

 joined the V. laminosa, a shell of a totally different figure 

 and appearance, and even the V. Casinato form his V. can- 

 cellata. 



English, Irish arid Scotch coasts, v. v. 



3. Venus Casina. Casino, Venus. 



Lister, pi. 28(5. f. 123 Pennant, pi. 57. f. 2jDa Costa, 

 pi. 13. f. 4, left hand fig. I,m. Trans, viii. pi. 2. f. 1. 



Shell thick, convex, white, with more or less of a deep 

 rufous-brown tinge, rounded and not elongated at the an- 

 terior side, with transverse raised thin ridges, sometimes 

 placed in pairs, and curved in a rounded manner towards 

 the hinge, but not breaking into tubercles at either of the 

 sides, nor striate longitudinally between them near the 

 beaks : beaks curved much to one side, with a heart-shaped 

 depression under them; one valve suddenly sloping inwards 

 at the cartilage side, and finely striate longitudinally ; in- 

 side white, with the margin finely notched : diameter two 

 inches. 



Da Costa' s figure is an excellent one, which Maton and 

 Rackett have referred to for V. verrucosa, and Dillwyn for 

 .V. cancellata. 



On the Scotch coasts, and Bray in Ireland, v. v. 



4. Venus 



