THE AVONDERS OF THE SIIOKE. G3 



(lisplciy the same orange hue as the mantle-lips, 

 and have a finer appearance than in the other 

 species ; the interior of the orifices in both is 

 covered with a layer of white pearly substance, 

 almost luminous. In the foot of tuhercvlatum, 

 which agrees, in the particulars already men- 

 tioned, with that of its congener, I observed a 

 beautiful opalescent gleam when under water." 



"C tuhercidalum" continues Mr. Gosse, " is 

 far the finest species. The valves are moi'e 

 globose and of a warmer color ; those that I have 

 are even more spinous." Such may have been 

 the ca.se in his specimens ; but it has occurred 

 to the writer now and then to dredge specimens 

 of C. aculcatitiii, which had escaped that rolling 

 on the sand fatal in old age to its delicate spines, 

 and which e«iualled in color, size, and pcrfect- 

 ness, the noble one figured in poor dear old 1)r. 

 Turton's " British Bivalves." Besides, ucnleatnm 

 is a far thinner and more delicate shell. And a 

 third P[)ecie(*, f\ erhinatxivi, with curves more 

 graceful and continuous, is to be found now and 

 then with the two former, in which each point, 

 instead of degenerating into a knot, as in (tibcr- 

 riilntuni, or developing from delicate, fiat, brier- 

 prickles into long, straight lliorns, as in arukatwn, 



