86 MUREX. ROCK-SHELL. 



by the curvature and groove along the upper and anterior 

 margin ; by the diagonal depressed line from the hinge to 

 the anterior front margin ; by its coarse and thick texture ; 

 and by the teeth. 



Da Costa's figure, from which that in the Dorset Cata- 

 logue is copied and most descriptions drawn, is a very in- 

 correct one ; and his text and all his references apply only 

 to M. Lutraria. Mr. Dillwyn, in his careless manner, gives 

 the length as about two inches, and the breadth rather 

 more than half as much. 



At the mouths of rivers : very rare. v. m. 



MUREX. ROCK-SHELL. 



Shell with a single valve, spiral, often rough 

 with membranaceous folds or protuberances: aper- 

 ture oval, ending in a straight entire canal, which 

 is sometimes a little reflected. 



1. Murex Carica. Date Rock-shsll. Fig. 26. 



Lister, pi. 880. f. 3. b. 



Shell pyramidal, coarse, thick, dull reddish-grey with a 

 few chocolate-brown longitudinal marks near the inner-lip, 

 irregularly striate and somewhat scaly lengthways ; about 

 the canal are a few transverse striae, on which there is a 

 broad raised rounded protuberance running a little ob- 

 liquely : spires six, hardly raised, with a row of seven or 

 eight pointed protuberances round the top of the two first 

 volutions, which on the body-one are concave and triangu- 

 lar, and about half an inch long ; these, however, become 

 gradually closed and . smaller, decreasing at length into 

 raised tubercles which become indistinct towards the 

 point ; the lesser volutions are finely striate circularly : 

 aperture triangular, large, extending to four-fifths of the 

 shell, and reaching to the second row of protuberances : 

 inside white, polished ; the outer-lip broad and thin, with a 

 few faint striae near the smaller end, which give the mar- 

 gin a slightly toothed appearance ; near the larger end the 

 margin protrudes into an angular hollow, in consequence 

 of its junction with one of the concave protuberance* : pi!- 



