CAVOLINID^. ,11 



3. DiACRIA MUCRONATA. 



Shell reddish coloured, pellucid, thin, triangular, transversely stri- 

 ated, undulated lengthwise, rounded anteriorly ; terminal spine 

 sharp, longer than the lateral ones. 



Hyalaea mucronata, Quoy Sr Gaim. Ann. Sc. Nat. x. 231, t. 8, f. 1, 

 2 ; D'Orb. Voy. Am. Mer. Moll. 108, t. 7, f. 6—10. 



Hyalaea trispinosa, Quoy ^ Gaim. Zool. Astr. t. 27, f. 17 — 19, ii. 

 378 (from Ann. Sci. Nat.) 



H. trispinosa, part, Desk, in Lamk. Hist. ed. 2, vii. 417, n. 4; 

 Pkilippiy Sicil. ii. 71. 



Hab. 



4. DiACRIA DEPRESSA. 



Shell elongated, triangular, superiorly dilated, inferiorly sharp 

 pointed, strongly arched, depressed, glossy, underneath three- 

 ribbed ; aperture narrow, semicircular, deeply cleft on each side. 



Hyalaea depressa, D'Orb. Voy. Am. Mer. Moll. 110, t. 7, f. 11 — 14 ; 

 Desk, in Lamk. Hist. ed. 2, vii. 422. 



Hab. 



5. DiACRIA LAEVIGATA. 



Shell somewhat round, depressed, thin, shining, glossy, hooked 

 posteriorly, shortly eared on each side. 



Hyalaea laevigata, D'Orb. Voy. Am. Mer. Moll. 110, t. 7, f. 15—19 ; 



Desk, in Lamk. Hist. ed. 2, vii. 423. 

 Hyale lisse, Voy. Bonite MolL t. 5, f. 14, 20. 



Hab. 



B. Shell without any lateral slit. 



3. CLIO. 



Animal elongate, conical, without lateral appendages. — Fins ex- 

 panded, united behind, without any small intermediate lobe. — 

 Shell elongate, angular, conical ; mouth larger than the cavity, 

 without any lateral slits. 



Clio (pyramidata), Broume^ Jam. 386, 1756 (not Pallas^ 1774, nor 

 O. F. Muller, 1776) ; Linn. Syst. Nat. ed. 12, 1094, 1767; Gmelin, 

 S. N. 3149. 



