120 VENEEIDyE. 



P. DECUSSATA, Linn, et nobis. 



Venus decussata, Auctorum. 



Tapes decussata, Brit. Moll. i. p. 3/9, pi. 25. f. 1. 



Animal thick, suboval, very pale creamy -white ; mantle 

 open, with the margins finely scalloped or deiitated. Foot 

 large, muscular, angulated, lanceolate, white, with a byssal 

 groove. Tubes subcylindrical, gently tapering, separate from 

 their bases, of the same length, and, when extended, as long 

 as the transverse measure of the shell ; they are at times 

 greatly inflated ; the colour, to within a quarter of an inch of 

 the orifices, is pale yellowish- white, interspersed with whiter 

 minute flakes, and marked for about an inch at their termi- 

 nations with confused yellowish-tawny or dark brown short 

 lines or blotches ; both the orifices are fringed, the branchial 

 with about twelve long cirrhi with alternate smaller ones ; the 

 anal has 16-20 of the same size, and generally both are of a 

 bistre colour; the siphons, at the animal's will, diverge in 

 various directions. There are a pair of suboval branchiae on 

 each side, the upper the smaller; they are more strongly 

 pectinated on the inner than on their external areas, of a pale 

 brown, aspersed with minute dark brown points. The palpi 

 are very small for the size of the animal, triangular and 

 striated as the branchial laminae. 



This species is much more common than the P. pullastra ; 

 they live together in the same shingles, and have precisely the 

 same habitudes; notwithstanding this community they are 

 very distinct species. 



P. VIRGINEA, Linn, et nobis. 



Tapes virginea, Brit. Moll. i. p. 388, pi. 25. f. 4, (>. 



- aurea, Brit. Moll. i. p. 392, pi. 25. f. 5. 

 Venus Sarniensis, anea, nitens, Turt. et Auctorum. 



Animal inhabiting a suboval shell, furnished with close-set, 

 blunt, rounded, stout, subconcentric striae ; the ground colour 

 is pale yellowish- white ; the mantle is open throughout the 

 ventral range, with its margins anteally dentated, medially 

 sinuatcd, and posteally crenulated, with a few short yellow 

 filaments at each extremity ; the animal emits anteriorly the 



