ASTARTE. 315 



This species is the Venus Danmonia (properly Dam- 

 nonia) of Montagu, V. Petagna of Costa, and Crassina 

 Britannica of Leach. The North-American form has 

 been called by Hanley A. latisulca, and by Gould A. 

 n n data. The variety elliptica is the Venus compressa 

 of Linne's ' Mantissa Plantarum/ Crassina ovata and 

 C. depressa of Brown, C. sulcata of Nilsson, A. Gai- 

 rensis of James Smith, and A. semisulcata of myself, 

 Loven, Moller, and Philippi, but not of Leach. 



2. A. compres'sa *, Montagu. 



Venus compressa, Mont. Test. Brit. Suppl. p. 43. t. 26. f. 1. A. compressa, 

 F. &H. i. p. 464, pi. xxx. f. 1-3. 



Body greyish-white : mantle plain-edged : tabes scarcely 

 perceptible outside the shell : foot white. 



Shell acutely triangular, nearly equilateral, rather convex, 

 thick, somewhat glossy : sculpture, sometimes only slight, irre- 

 gular, and scarcely elevated ridges in the line of growth, but 

 more commonly also close concentric ribs on the umbonal area ; 

 the surface is covered, as in the last species, with liner inter- 

 stitial striae : colour milk-white beneath the epidermis, which 

 is of various hues from yellow to chestnut-brown, and is seen 

 under the microscope to be reticulated lengthwise by innume- 

 rable rows of punctures : margins curved in front, obtusely 

 angular or truncate on the anterior side, with a sharply rounded 

 point, and sloping or gently curved on the posterior side to a 

 blunter point : beaks almost central, considerably recurved to- 

 wards the anterior side : lunide and corselet deep and nearly 

 smooth : ligament cylindrical, of moderate length, yellowish- 

 brown, not projecting beyond the dorsal line, partly contained 

 in a groove on the hinge-plate : hinge-line nearly rectangular : 

 hinge-plate thick and broad, occupying about two-fifths of the 

 circumference : teeth as in A. sulcata, but the cardinals are 

 proportionally stronger, and the anterior laterals (especially 

 that of the left valve) are more developed : inside porcellanous. 

 slightly nacreous, and minutely tubercled ; margin sharp and 

 smooth, bordered within by a slight but distinct ridge, forming 



* Squeezed together. 



p 2 



