50 Lamarck's Genera of Shells. 



Shell fusiform-turrited, ventricose, transversely sulcated and 

 striated ; white, clouded with red ; furrows tubercular ; the middle 

 part of the last and penultimate whorl, surrounded by a single row 

 of larger tubercles; beak ascending. American Seas. PI. v. 

 Fig. 181. 14 Recent species, and 1 fossil. 



10. Murex*. 



Shell oval or oblong, channelled at the base ; rough, spinous or 

 tubercular varices on the exterior surface. Aperture rounded, or 

 sub-oval. Three or more varices on each whorl of the spire, the 

 lower ones uniting obliquely with the upper in uninterrupted lon- 

 gitudinal rows. Operculum horny. 



The Linnean genus murex comprehended a great variety of very 

 different shells, confusedly jumbled together under one name. In 

 it were found several of the cerithia, at least one pleurotoma, a 

 turbinella, a cancellaria, two fasciolarioe, several fusi, and pyrulse, 

 struthiolaria, and ranella, murex proper, and some tritones. Bru- 

 guiere reduced the murices to those shells which have constant 

 external varices, and Lamarck has divided these further, into the 

 three separate genera of ranella, murex, and triton, each containing 

 a considerable number of species. 



Of all the variciferous shells, the murex has the greatest number 

 of varices, of which there are at least three, and frequently more, 

 on each whorl ; if we count those on the lowest whorl, we shall find 

 that they coincide, though somewhat obliquely, with the varices of 

 the upper whorls, the whole forming longitudinal rows on the shell, 

 inclining towards one side, near the summit of the spire. 



The struthiolaria has only one varix, which is on the right lip ; 

 the ranella two, at opposite sides of the shell ; and the murex 

 three, or more. 



Type. Murex hrandar is \. (Idem. Linn.) 



Shell subclavate, anteriorly ventricose, caudate, whitish ash 



* The name used by Virgil and Horace for the shell fish from which the 

 Tyrian dye of the aucients was obtained ; which, according to Columna was the 

 Purpura patula of Lamarck ; the Buccinum palulum of Linneus. 



t Lamarck's second species. His type is M. cornutus. 



