TRIBE ARCACEA. 7 
* * Inner margin crenulated. 
A. Hetprnent. Lam. 24.—A. Canpipa. Gimel. 3311.—D. 
p. 228.—Ch. f. 542.—W. t. 9. f. 7. Transverse, anteriorly pro- 
duced, posteriorly truncated, white under a scaly epidermis, with 
longitudinal crenulated grooves, which are in pairs at the anterior 
end: beaks approximated, margin gaping and somewhat crenu- 
lated. 2.—Guinea and Brazil.—“ Probably a variety of Ovata.” 
DesuH. 
A. Scarua. Lam, 25.—Ch. f. 548. Transversely oblong, 
ventricose, thin, white with the umbones reddish and oblique ; 
with from twenty-nine to thirty-four ribs, which are divided into 
two portions by a groove, (which is narrow but almost as deep as the 
spaces between the ribs,) and are narrow and prominent parti- 
cularly on the anterior side. 5—India ?—W. Indies ? 
A. AntiquaTa. Lin. 1141.—D. p. 232.—Lam. 26.—W. t. 
9. f.17.—Ch. f. 548.—E. t. 306. f. 2.—Gual. t. 87. c. Trans- 
versely ovate, obliquely heart-shaped, thick, white, ventricose, with 
numerous flattened ribs, which are transversely striated, unarmed 
and the posterior ones bifid: anterior side slightly angulated: area 
between the beaks not grooved. 2..3.—Mauritius, Mada- 
gascar, Jc. 
A. RuomBeA. Born.—Gmel. 3314.—D. 233.—Lam. 27.— 
Ch. f.553.—E. t. 307. f.3.—W. t. 9. f. 19. Heart-shaped, nearly 
as long as broad, gibbous, white covered by a brown epidermis, 
with about twenty-six longitudinal transversely striated ribs, and 
their interstices nearly smooth: beaks incurved and distant, the 
area between them rhomboidal. 14. .13.—W. Indies.—EH. Indies? 
A. Granosa, Lin. 1142.—D. p. 233.—Lam. 28.—W. t. 9. 
F-18:— Tas... 24). f. 78:—Ch.f. 557.—Knorr. 3. t. 4. f. 2.— 
Sow. G.—Reeve. t. 82. f. 3. Heart-shaped, nearly as long as 
broad, very ventricose, thick, almost equilateral, with upwards of 
twenty rounded ribs, armed with orbicular, somewhat spinous 
nodules, white within, and without, tinged slightly with brown at 
the beaks, which are incurved and rather distant with the area 
between them covered with a dark brown ligament, marked with 
rhomboidal grooves. 12. . 2.—Indian Ocean. 
A. Auricutata. Lam. 29.—Del. t. 11. f. 12.—Savig. 
Ligyp. t. 10. f. 8. Heart-shaped, ventricose, white, under a hairy 
epidermis, with about twenty-eight strong radiating crenulated 

1 Deshayes separates as confounded with this, a species which I 
propose to name in honour of that laborious savant, A. Drs« 
HAYESII.—Crual. t. 87. B.—H. t. 306. f. 1. Oblong, rather thin, 
with rounded ribs and the area between the beaks marked with 
lozenge-shaped grooves. 
