260 MALACOZOA. TRUPIOPODA. LAMELLIBKANCHIATA. 



much shorter ; the nmbones pointed, contiguous, and curved 

 forwards; the dorsal line nearly straight, elongated, with a 

 linear-lanceolate, obliquely striated impression, of which the 

 sides slope inwards, the anterior slope concave, with a narrow- 

 lanceolate obliquely striated impression with concave sloping 

 sides; the valves moderately thick, with about twenty-two 

 broad, little elevated ribs, which toward either end become 

 obsolete, and, as well as their interstices, which are about the 

 same breadth, are concentrically striated ; the epidermis light 

 yellowish-brown or umber-brown ; two divergent strong teeth 

 in one valve, a strong central tooth in the other ; inner surface 

 white or bluish-white, glossy toward the margin, which is not 

 crenate. Length an inch and four-twelfths, height an inch. 



This species is easily distinguished by its being elliptical, 

 more compressed, especially toward the ventral margin, with 

 the teeth more divergent, and the concentric ridges evanescent 

 at both ends. 



Crassina elliptica. Brown, Illustr. PI. 18. f. 3.- Crassina ovata. 

 Brown, Edinb. Journ. of Nat. and Geogr. Sc. I. 12. PI. f. 8. — 

 Crassina depressa. Brown, Illustr. PI. 18. f. 2. 



5. Astdrte multicostdta. Many-ribbed Astarte. 



Shell trigonal, moderately convex ; with the anterior end 

 slightly longer; the umbones contiguous, rather pointed and 

 somewhat curved forwards ; the dorsal slope slightly convex, 

 with a narrow lanceolate, obliquely striated impression, of 

 which the sides slope inwards, the anterior slope somewhat 

 concave, with an oblongo-lanceolate, obliquely striated im- 

 pression, with concave sloping sides ; the valves thick, with 

 about forty concentric convex ridges, which are rather broader 

 than the interstices, and, as well as they, faintly concentrically 

 striated ; the epidermis yellowish-brown, or olive-brown, and 

 glossy, usually patched with a black crust ; two strong teeth 

 in the left valve, a median stronger tooth and two small teeth 

 in the right ; inner surface white, dull, glossy toward the mar- 

 gin, which is not crenate. Length half an inch, height nearly 

 the same. 



Easily distinguished from Astarte sulcata by its much more 

 numerous ruga?, more trigonal form, and smooth margins. 

 The young are much compressed, with a very thin margin, 

 and brownish-yellow epidermis, and have some faint resem- 

 blance to those of Cyprina Islandica. 



Common in deep water, and on hard ground, off Aberdeen; 

 frequently brought up by the lines. 



