350 TESTACEOUS MOLLUSCA. 



On Crassina (p. 87). Consult Sowerby's monograph (Th. Con. 2) 

 and Proc. Philad. 3. The name Astarte has priority. 



Mactra Veneriformis (W. S. 1. 1, Mac. f. 8) is the young of C. lactea 

 (p. 88); A. Cyprinoides of Duval, and A. corrugata of Brown, are 

 synonyms of Arctica (p. 89). 



Crassina latisidca, p. 87, t. 14, f. 35 ... C. incrassata, p. 88, t. 14, 

 f. 39 ... C. castanea, p. 88, t. 9, f. 97. 



Crassina elliptical (t. 14, f. 36), Brown, II. C. B. 96, pi. 38, 

 /. 3. — C. ovata, Brown, II. C. B. — C. sulcata, Nils. N. A. Holm. 

 1822. — Astarte semisulcata, Phil. N. C. 2, p. 57, Ast. t. 1, /. 10. 

 —A. e. Br. Mol 1, p. 459, *. 30, /. 8.— Sow. Th. 2, p. 779, t. 167, 

 /. 4. Elliptically or ovately subcordate, compressed, much produced 

 and obtusely (yet not broadly) biangulated in front, convex or sub- 

 arcuated ventrally, rufous (more rarely olivaceous) brown, fulvous at 

 the umbones, with concentric striolse, and more or less depressed and 

 rounded concentric ribs, which latter are moderately distant, at least 

 as broad as their intervals, and obsolete beyond the umbonal ridge, 

 and near the internally simple ventral margin : beaks inclined, at 

 one-third the distance from the rounded hinder extremity: scars 

 large. !.£...-§-. Scotland. 



Crassina Banksii. — Nicania B. Leach,\Voy. Ross. — Astarte B. 

 Beech, Z. t. 44, /. 10 (well).— Sow. Th. 2, p. 781, t. 147, /. 8 (not 

 so well). Oval-subtriangular, equilateral or nearly so, moderately 

 thick, only subventricose but swollen at the umbones, covered with a 

 glossy brownish yellow cuticle, finely striated concentrically ; ventral 

 edge entire, arcuated behind, straighter in front; dorsal slopes de- 

 cided, nearly equal, the anterior one straight, the posterior one in- 

 curved ; front extremity contracted, and bluntly subbiangulated ; 

 hinder extremity narrowly and obtusely rounded ; beaks very promi- 

 nent. 4-. Arctic 0. The above has been drawn up from Leach's 

 types ; and does not suit our figure (pi. 14,/. 37^), which looks more 

 like the British compressa (Montagui). 



Crassina striata (t. 14, f. 38). — Nicania s. Leach, Toy. Boss. — 

 A. s. Beech, Z. t. 44,/. 9. Transverse, subequilateral, ranging from 

 cordiform-elliptic to subovate-cordiform, not very thick, yellow-brown, 

 densely lyrated throughout with raised striae, which are narrower than 

 their intervals, subarcuated and entire ventrally; extremities nar- 

 rowed, the front one convexly subtruncated, the hinder one rounded ; 

 umbones prominent ; beaks acute, inclined ; lunule deep, cordate- 

 lanceolate ; ligament sunken, not half so long as the impressed area ; 

 teeth rather small. \. Greenland. 



Crassina Arctica,- (t. 14, f. 40, as Cyprinoides).— C. compressa, 

 Mont. t. 26, lower /. 1 {not desc) — C. A. Gray, Parry. — Astarte c. 

 Duval, Her. A. 1841, p. 278. — A. com. Mctcg. — C. corrugata, 



