o52 HAMINEA. 



Genus HAMINEA Leach, 1847. 



Haminea Leacli MS. Gray, P. Z. S., 1847, p. 161 (H. hydatis). 

 A. Ad., Thes. Conch., ii, p. 557. — Sowb., Conch. Icon., xvi. — Vays- 

 siERE, Ann, Sci. Nat. Zool., ix, 1879-80, and Recherches sur les 

 Moll. Opisthobr., Ire pt., Tectibranches, Ann. Mus. d'Hist. Nat. 

 Marseille, Zool. ii, p. 18, 1885, (anatomy). — Hamincea Leach, 

 Moll. Gt. Brit., p. 40, 1852. 



Shell thin and rather fragile, unicolored, corneous, yellowish or 

 greenish, covered with a thin cuticle, globose, ovate or cylindric- 

 oval, the spire sunken and concealed, vertex concave, imperforate or 

 minutely perforate ; body whorl large; aperture as long as the 

 shell, broadly rounded below, narrow above ; columella simply con- 

 cave, thin, its edge narrowly reflexed, showing a slight fold where it 

 joins the body of the shell; lip retreating above, but not distinctly 

 sinused. Type B. hydatis L. 



Animal capable of retraction into the shell; cephalic disc large, 

 truncated in front, strongly bilobed behind, the eyes small. Mantle 

 rudimentary, covered by the shell. Epipodial lobes large, reflexed 

 over and partially covering the shell, (pi. 43 fig. 6). Sole long, 

 tapering behind ; gizzard very muscular, armed within with three 

 large corneous curved plates (pi. 48, figs. 2, 3), and three pairs of 

 small plates. (See pi. 48, fig. 1, U. navicula; also figs. 9 to 13). 



Radula having the formula oc , 1, 1, 1, oo , Central tooth small, 

 adjacent laterals large, with a long serrate cusp; uncini many (55 

 in H. navicula) with long, simple cusps. 



The shell in this genus differs from all other Akeridce in being 

 more compactly convoluted with less developed posterior sinus in 

 the outer lip. It differs from Bulla in being thin, unicolored and 

 imperforate or nearly so at vertex. The anatomical distinctions 

 from Bulla are many and important; and it is not easy to see why 

 Fischer placed Haminea untler that group as a subgenus. 



The anatomy has been studied and figured by Vayssiere, and the 

 shells have been monographed by Arthur Adams and Sowerby. A 

 good figure of the dentition is still lacking. 



No useful subdivision of the group other than a geographic one 

 can now be made, although the different modes of the insertion of 

 the outer lip at the vertex offers a good character (compare H. nav- 

 icula with H. elegans Gray). The animals of the European and 

 West Indian species seem to have a finely peppered or dotted 



