MURICIDiE. 113 



Shell purpuriform ; inner lip flattened and depressed, but outer 

 lip, when adialt, thickened, inflected and toothed ; aperture wide. 



usiLLA, H. Adams. Founded on V.fus^co-nigra, Pease, which 

 diflTers from the typical Vexilla in the spire being acuminate, and 

 the aperture somewhat contracted or narrowed. 



Pease (Am. Jour. Conch., iv, 115) adopts the subgenus, and 

 adds to it Purpura leucostoma, Desh., and Planaxis cingulata, 

 Gould. I ver}' much doubt whether the group will stand, as the 

 little specimen of Pease's species before me is very suggestive 

 of Pisania, and Deshayes' species is a true Purpura, and evidently 

 very closely allied to, and as I believe = P. columellaris. The 

 opercula of Pease's and Gould's species are unfortunately unde- 

 scribed. 



RiciNULA, Lam. 



Etym. — Diminutive of ricinus, the (fruit of the) castor-oil 

 plant. 



Syn. — Canrena, Link. Drupa, Bolt. Pentadactylus, Klein. 



Distr. — R. horiHda, Lam. (xliv, 28, 29). 30 sp. India, China, 

 Philippines, Australia, Pacific, Panama, Red Sea, Natal, West 

 Indies, Brazil. 3 fossil sp. Miocene — ; France. 



Shell ovate, solid ; spire short, whorls tubercular or spinous ; 

 aperture linear, narrow, contracted by callous projections, with 

 a short, oblique, emarginate canal in front ; inner lip tubercularly 

 wrinkled ; outer lip internally with plait-like teeth, often digitate. 



siSTRUM, Montfort. (Morula, Montf.) Has usually a longer 

 spire, the shell is smaller, more fusiform, the teeth within the 

 outer lip not grouped, but single. This separation has its con- 

 veniences : nevertheless the characters, as in so many other 

 groups, only serve well for the recognition of some of the forms ; 

 others must be arbitrarily placed. The dividing line between 

 Sistrum and Engina, Latirus and some Pisanoid species is very 

 difficult to trace. The group is essentially Polynesian in distri- 

 bution, frequenting coral reefs. R. morus, Lam. (xliv, 30). 



MoNOCEROS, Lam. 



Etym. — Monos, one, ceras, a horn. 



Syn. — Acanthina, Fischer. Rudolpha, Schum. XJnicornus, 

 Montf. 



Distr.— 10 sp. California to Chili. Tertiary of Chili. M. 

 gigante/um, Lesson (xlv, 41). M, laguhre, Sowb. (xlv, 42). 



Shell ovate, last whorl large ; spire rather elevated ; aperture 

 semilunar ; inner lip wide and flattened ; outer lip crenated, with 

 a prominent tooth at the fore-part, 



PsEUDOLivA, Swainson. 

 Etym. — Resembling Oliva. * 



Syn. — Sulcobuccinum, d'Orb. Gastridium, Gray. Buccinorbis, 

 Conr. Pseudodactylus, Herm, 



