Myrtea. MOLLUSCA. VENERID^. 443 



EXTINCT SPECIES. 



1. L. divaricatula Orbicular, gibbose, marked with two sets "of oblique 



arched stride, and three or four deep lines of growth.— Sower. Min. Conch. 



t. ccccxvii. London Clap. — Lamark and Sowerby agree in ^considering it as 



identical with the recent L. divaricata of the West Indies ! 



2. L. mitts Orbicular, convex, ornamented with minute longitudinal 



strije, and numerous small regular concentric laminae ; lunette oval, very con- 

 cave ; cardinal teeth obscure, no lateral tooth.— Sower. Min. Conch, t. Dlvii. 

 — London Clay. 



3. L. antiquata Orbicular, convex, ornamented with concentric laminae ; 



surface irregular; anterior side angular; lunette flat, lanceolate. — Sower. 

 Min. Conch, t. Dlvii. f. 2 — In Crag. 



4. L. crassa Nearly orbicular, convex ; covered with thick slightly ele- 

 vated concentric laminae ; superior margin obtuse ; lunette linear ; concealed ; 

 valve thick. — Sower. Min. Conch, t. Dlvii. £ 3.— Oolite. 



Gen. CXXV. MYRTEA.—" Oval-triangular, equivalve, 

 nearly equilateral, closed ; hinge of one valve, with a single 

 tooth and lateral one each side ; of the other valve, two 

 teeth, the lateral ones obscure.'" — Turton. 



509. M. Spinifera. — Shell with about thirty-six regular, con- 

 centric, elevated, and somewhat reflected, ridges. 



Venus spin, Mont. Test. Brit. 577- t. xvii. f. i. — M. spin. Turt. Biv. 

 Brit. 133. — Western coasts of England, rare. 



Length half an inch, breadth a little more ; yellowish-white ; the ridges 

 become confluent in pairs on the retral edge, forming short obtuse reflected 

 spines ; beaks small, nearly central, inclining, below which is a lanceolate de- 

 pression. 



VENERIDiE. 



Gen. CXXVI. CYPRINA. — Shell subcordiform, nearly 

 equilateral, closed, hinge with three diverging teeth, and a 

 remote lateral one at the retral termination of the liga- 

 ment ; syphons not produced, leaving the marginal impres- 

 sion of the cloak entire, resembling, in this character, the 

 genus Astartc. 



— 510. C. islandica. — Obliquely heart-shaped, beaks prominent, 

 concentrically striated, and covered with a thick brown cuticle. 



Concha e maximis, List. An. Ang. 173. Conch, t. cclxxii.— Venus isl. 

 Linn. Syst. i. 1131. Mull. Zool. Dan. t. xxviii. f. 1-5. Mont. Test. 



