284 MALACOZOA. TROPIOPODA. LAMELLIBRANCHUTA. 



it differs more especially in having the posterior end 

 more elongated, and in being more open at both ends ; 

 and from the former in having the ends less open. La- 

 marck's observation that the Psammobise " n'ont point 

 le pli irregulier du cote anterieur des Tellines," is in- 

 correct. 



1. Psammobia Feroensis. Feroese Psammobia. 



Shell oblong, much compressed, anteriorly rounded, pos- 

 teriorly obliquely truncate and angular, finely striated concen- 

 trically, with a prominent line from the umbo to the posterior 

 angle, and several less distinct lines between it and the dorsal 

 margin, the striae more elevated on these lines ; the colour 

 reddish-white with radiating pink bands ; the epidermis yel- 

 lowish-brown ; the inside pinkish- white. Length an inch and 

 three-fourths, height ten-twelfths. 



Young individuals lamelloso-spiniferous on two bands in 

 each valve, from the umbo to the angles of the posterior trun- 

 cation. 



Not very uncommon along the sandy shores, from Aber- 

 deen to Collieston ; sometimes cast on the beach, arid occa- 

 sionally brought up by the fishing-lines : Gamrie, Banffshire, 

 Miss Macgillivray ; Cruden, Mr. Murray. 



Tellina Feroensis. Gmel. Syst. Nat. 3255. Psammobia Fer- 

 roensis. Turt. Brit. Biv. 94. PI. 8. f. 1. Tellina incarnata. Penn. 

 Brit. Zool. iv. PI. 47. f. 31. Tellina Feroensis. Mont. Test. 

 Brit. 55. Psammobia Ferroensis. Flem. Brit. Anim. 438. 

 Psammobia Feroensis. Lamk. Syst. v. 512; Ed. 2. vi. 172. 



GENUS 3. SAXICAVA. 



Animal oblong, subcylindrical. The mantle closed, 

 prolonged behind into a tube, internally double. Foot 

 small, elongated, compressed, pointed. Branchiae very 

 unequal. Mouth moderate, with four small labial ap- 

 pendages. Adductor muscles moderate, anterior smaller, 

 cylindrical. 



Shell oblong, convex, very inequilateral, rather thick, 

 covered with an epidermis ; the umbones rather promi- 

 nent, curved a little forwards ; the anterior end shorter 

 and rounded ; the posterior prolonged, and angulate 

 or rounded. Hinge with very small divergent teeth, 



