118 OCINEBRA. 



attacks the living oyster ; the Nassa and Nqtica, on the contrary, 

 living on dead flesh, and possessing a delicate sense of smell 

 which enables them to perceive from a great distance the pres- 

 ence in the water of a decaying animal. 



Murex torosus, Lamarck, (fig. 404), is considered with some 

 doubt, a monstrous variety of this species. The spire is much 

 shorter, and but for the remains of varices, nearly hidden under 

 the nodules of the revolving ribs the form and appearance are 

 very suggestive of Pur pur a, and particularly of Pur pur a cin- 

 gulifera, L., (P. trochlea, Lam.), of South Africa. This variety (?) 

 comes from Sicity and Algiers. 



M. EDWARDSI, Payr. PL 36, figs. 410-412. 



This little shell, as Reeve remarks, appears to oscillate between 

 Murex and Purpura ; its dark aperture, toothed lip and numerous 

 ribs recalling the latter, whilst the occasional appearance of two, 

 three, or more distinct varices indicates Murex. Varies consider- 

 ably in form ; sometimes the whorls are well-rounded above, some- 

 times shouldered in the latter case the ribs become nodulous on 

 the shoulder. Light brown, purplish or livid within ; frequently 

 an obscure light band on the periphery. 



Length, *8 inch. 



Mediterranean, 'So. Atlantic coasts of Spain, Portugal, Madeira, Canaries. 

 The typical form on rocky bottoms at small depth, the variety ( = P. 

 nux, Reeve), on sand at 4 to 8 fathoms. 



Reeve has figured the variety with a shoulder, and no varices 

 as Purpura nux ; but every intermediate grade of form and de. 

 velopment of varices exists, so that it cannot be separated from 

 the type except as a mere inconstant variety. 



M. PUMILUS, Kiister. PL 36, fig. 413. 



This little shell, only about one-fourth inch in length is very 

 probably the same as M. Edwardsi, var. nux ; to which Kobelt 

 doubtfully refers it. ^ unknown. 



The specific name is twice preoccupied by Broderip and A. 

 Adams ; the species is too doubtful to rename. 

 M. SEMICLAUSUS, Kiister. PL 36, fig. 414. 



A shell about '35 inch long, having close relationships with 

 M. Edwardsi. ^ unknown. 



