82 TESTACEOUS MOLLUSCA. 
dark purple ray bordering the anterior slope near the beaks : no 
posterior or lateral tooth. 1.—Africa. / 
** Inner edge crenated. 
D. Rueosa. Lin. 1127.—D. p. 159.—Rueosa in part.— 
Lam. 17.—Knorr. 6. t. 28. f. 8.—#. t. 262. f. 3.—Ch. f. 250.— 
W.t. 6. f. 3. Elongated, wedge-shaped, inflated, anteriorly ex- 
tremely short obtusely and almost directly truncated, the slope 
angulated at its edge and roughened by transverse coarse grooves 
desussated by radiating strie: variable in colouring, being Siateh 
or pale drab, sometimes with purple rays, or reddish with deeper 
zones, covered with simple rather fine radiating striz : ventral 
edge not incurved and little arcuated. 3..1}.—S. America.? 
D. Srriara. Lin. (not Chemnitz.) D. p. 151.—List. t. 
376. f. 219.—Knorr. 6. t. 7. f. 7.— Gualt. t. 89. D.— FE. t. 262. 
f- 5. Sub-triangularly cuneiform, inequilateral, covered with strong 
radiating strice, variable in colouring but usually dull white or reddish 
with darker concentric bands, posterior dorsal edge much sloping, 
the ventral arcuated in the middle, but pubscanyad at the sides : 
anterior slope sub-biangulated (sharply so at the umbonal slope) and 
marked with strong radiating strie: margin internally dentated : 
two lateral teeth in each valve. $..12.— West Indies. 
D. Cayennensis. Lam. 18.— Del. t. 6. f. 13. Somewhat 
triangular, white slightly tinged with purplish, short and obtusely 
truncated anteriorly, with fine longitudinal grooves, and the sides of 
the anterior slope sub-biangulated : beaks reddish purple.— Guiana. 
—Less tumid but akin to the last. 
D. Eroneata. Lam. 19.—Adanson. t. 18. f. 1.—Seba. 3. t. 
86. f. 10.2? Transversely elongated and longitudinally grooved, 
very obtuse anteriorly ; the grooves at the anterior end sub-denticu- 
lated: violet within.—Variety.—Very pale fulvous and white 
within.— W. Africa. 
D. Denticutata.* Lin. 1127.—D. p. 151.—Lam. 20.—Ch. 
J. 256.—E. t. 262. f. 7.—Don. t. 24.—W. t. 6. f. 8. Ovate, 
wedge-shaped and very obtuse anteriorly, with numerous fine 
punctured longitudinal strize, white with purple rays : anterior slope 
ey wrinkled and the margin toothed; purple within. 
s5..42.—Mediterranean and West Indies. 
D. Carprores. Lam. 21.—Ast. t. 81. f.17, 8, 9.—Del. t. 



1 See too the Raprata of Schreeter (of which we have given a 
copy) ¢.8.f. 3. p. 104.—D. p. 155.—W. t. 6. f. 17. 
2D. Rincens, Lam. 16. is a Capsa. 
3 Delessert’s figure of CAYENNENSIS so well agrees with some 
varieties of the preceding, that I can hardly venture to consider the 
species distinct. 
