954 MELANIIDA. 
somewhat doubtful; it may belong to the Rissoide. M. Hupen- 
sis, Gredler (1xx, 92). 
PrycHostytus, Sandberger. 
Distr.—P. harpeformis, Dunker. Wealden, Europe, 
Shell egg-shaped, with scalariform, sharp spire; whorls ribbed 
transversely ; mouth small, acutely angular behind, somewhat 
wider and rounded in front; columella folded. 
Doryssa, H. and A. Adams. 
Distr.—17 sp. Eastern South America. D. brevior, Troschel 
(Ixxv, 93). 
Shell turreted, longitudinally plicate, decussated by revolving 
sulcations ; aperture effused at the base, right margin uncinately 
produced. ’ Operculum spiral with sinistral subcentral nucleus (7). 
CLAVIGER, Haldeman. 
Syn.—Vibex (Oken), Gray. 
Disir.—t sp., Africa. C..auriia, Lam. (1xxi,.94). 
Shell turreted, with revolving carinze or tubercles; aperture 
subproduced at the base, subcanaliculate, outer margin sinuous, 
two to four plice within. Operculum paucispiral; nucleus basal, 
submarginal, sinistral. 
TipHopra, E. A. Smith. 
Distr.—Lake Tanganyika, Africa. #. Horet, Smith (1xxi, 95). 
Shell subturbinate, spire depressed; whorls flattened above 
angulated and spinose; axis and aperture prolonged into a 
channeled beak. 
Similar in form to the American genus Io. The operculum is 
unknown. It has been referred temporarily to the family Mela- 
niideze, but is quite as closely allied, I think, to the fresh-water 
division of the Cerithiidze, and especially to the Siamese genus 
Brotia. 
HEMISINUS, Swainson. 
Syn.—Basistoma, Lea. Tania, Gray. 
Distr.—36 sp. So.and Central America, W. Indies, Seychelles, 
Australia. H. lineolatus, Wood (1xxi, 96). 
Aperture canaliculated at. the base, columella not callous. 
Operculum paucispiral; nucleus basal, sinistral, marginal or 
submarginal. 
VERENA, H. and A. Adams. Shell turbinated, shouldered and 
coronated, spirally striate; aperture subtruncated anteriorly, 
forming a short, wide canal. South America. #H. crenocarina, 
Morice. (1xxi, 97). 
MELANopsis, Ferussac. 
Syn.—Bulliopsis, Conrad. Coptostylus and Campylostylus, 
Sandb. 
