BUCCINIDjE. MURICIILE. 377 



menta; which are of various forms in the different species, and 

 are attached in different modes. That of the Buccinum is often 

 to be met with on our shores, in the form of a large irregular 

 ball, composed of a number of little vesicles attached together. 

 The Purpura forms a large number of distinct cylindrical cases, 

 which it attaches to the rocks it inhabits. Each of these small 

 cases gives birth to several young, but it is remarkable that 

 these are exceedingly few in comparison with the number of 

 apparent eggs contained in the capsule when just deposited. Of 

 these there are several hundreds, but it seems doubtful whether 

 they are all to be regarded as true eggs. The Norwegian Zool- 

 ogists, Koren and Danielssen, who consider them as real yelks, 

 assert that a number of them combine to form one young Mol- 

 lusk ; whilst Dr. Carpenter, who has paid great attention to the 

 subject, asserts that the young are formed in the usual way from 

 a single true yelk, and that the other similar bodies serve these 

 young as food. The evidence at present appears to be in favour 

 of the latter view. 



991. In the MURICIDJE, or Rock-shells, the animals of which 

 closely resemble those of the Buccinidse, the shell is furnished 

 with a canal for the reception of the siphon, projecting straight 

 from the anterior extremity. The species are exceedingly 

 numerous, and occur abundantly in all seas. Many of them at- 

 tain a large size, and the animals of some are eaten. One of these 

 is the Fusus antiquus, a well-known Whelk, which is said to be 

 preferable to the common Whelk (Buccinum). The shell of this 

 species is employed as a lamp in the Shetland cottages ; it is 

 suspended horizontally, and filled with oil, when the canal serves 

 for the reception of the wick. In many cases the shells exhibit 

 ridges on their surface (called varices) which correspond with the 

 margins of the aperture of the shell at former stages of its 

 growth. This is well seen in the true Murices, of which one 

 species (Murex erinaceus) is so abundant on our south coasts, 

 that its shell is one of the commonest objects on the beach. The 

 ridges in other species are armed with spines, as in the Murex 

 tenuispina (Fig. 656), in which the canal also is greatly elongated. 

 As already stated, the Tyrian purple was obtained from species of 



