pusus. 193 



epidermis ; has a long spire with rounded whorls^ and 

 numerous longitudinal ribs crossed by raised lines. 

 B. acuminatum: the beautiful tapering spire with sloping- 

 sides, and the regular bead-like granulations of the 

 spiral lines, in the elegant but rare shell to wliich this 

 name is applied, render me unwilling to admit that 

 it is but a variety of B. undatum. In spite of the 

 curious and monstrous forms known to occur in that 

 species, I cannot resist the conclusion that the form of 

 B. acuminatum is normal and distinct. 

 YI. Fusus. — ^The shells of Fusi are more tapering than 

 those of Buccinum at the canal end ; the operculum has its 

 nucleus at the end, not at the sides. The foot of the animal 

 is not so spreading ; the siphonal fold is not so much pro- 

 duced ; and the eyes, instead of being placed at the base 

 of the tentacles, are at the end of thickened portions half- 

 way up. 



The nest for hatching the fry of Fusi is curious in all 

 the species. That of F. Norvegicus consists of a lens-shaped 

 bag, of an inch diameter, glued to the inside of shells, Mr. 

 Howse, in a paper in the ' Magazine of Natural History,' 

 gives an account of some which he examined. He says : — 

 ^''The envelope is coriaceous, of a horny appearance, very 



o 



