350 TESTACEOUS MOLLUSGA. 
On Crasstna (p. 87). Consult Sowerby’s monograph (Th. Con. 2) 
and Proc. Philad. 83. The name Astarre has priority. 
Mactra Veneriformis (W.S. t.1, Mae. 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 latisulca, p. 87, t. 14, f. 85 ... C. incrassata, p. 88, t. 14, 
f. 39 ... C. castanea, p. 88, t. 9, f. 27. 
CRASSINA ELLIPTICA* (t. 14, f. 36), Brown, Il. C. B. 96, pl. 38, 
f. 3.—C. ovata, Brown, Il. C. B.—C. sutcata, Nils. N. A. Holm. 
1822.—AsTARTE SEMISULCATA, Phil. N. C. 2, p. 57, Ast. t. 1, f. 10. 
—A. 8. Br. Mol 1, p. 459, t. 30, f. 8.—Sow. Th. 2, p. 779, t. 167, 
f. 4.  Hlliptically 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 striole, 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. 11...8. Scotland. 
CrasstnA Banxsit.—Nroania B. Leach,Voy. Ross—Astarte B. 
Beech, Z. t. 44, f. 10 (well).—Sow. Th. 2, p. 781, t. 147, f. 8 (not 
so well). Oval-subtriangular, equilateral or nearly so, moderately 
thick, only subventricose but swollen at the umbones, covered with a 
lossy 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. 3. Arctic O. The above has been drawn up from Leach’s 
types; and does not suit our figure (pl. 14, f. 387), which looks more 
like the British compressa (Montagui ). 
CRASSINA sTRIATA (t. 14, f. 88)—Nrcanta s. Leach, Voy. Ross.— 
A. s. Beech, Z. t. 44, f.9. Transverse, subequilateral, ranging from 
cordiform-elliptic to subovate-cordiform, not very thick, yellow-brown, 
densely lyrated throughout with raised striz, 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. 4. Greenland. 
Crasstna Arctica,* (t. 14, f.40, as CyprtNorpEs).— C. COMPRESSA, 
Mont. t. 26, lower f. 1 (not dese.\—C. A. Gray, Parry. Astartr c. 
Duval, Rev. Z. 1841, p. 278.—A. com. Macg.—C. corrueata, 
