THE TROCHI. 83 



PEAEL-SHELLS. 



Of the shelled Molliisca which the dredge ever and 

 anon brmgs up, the TrocJii Sive among the most con- 

 spicuous for beauty. T. ziziphinus is exceedingly 

 common in deep water, and not rare within tide- 

 marks. Its very regularly conic form, and the blotches 

 of dark purple that run in a spire round and round 

 the shell, are pleasing to the eye ; and the ani- 

 mal, which crawls freely in confinement, is richly 

 coloured, being of the tint of a ripe melon, striped 

 with black. {See Plate I.) One or two specimens 

 of a pm'e white variety of this species have occurred 

 to me. 



Though this is a shell of considerable size, it is ex- 

 ceeded in that respect, and (in the estimation of some, 

 probably) in that of beauty also, by T. granulatus. 

 The latter is esteemed a somewhat rare shell ; but in 

 this Bay, and off Portland, it is not at all micommon. 

 In shape it is equally elegant with the former, the shell 

 tapering to a conical point, and displaying a sm*face 

 sculptured with spiral raised lines, each of which is 

 composed of a number of minute rounded knobs, like 

 a sti-ing of beads. Its texture is somewhat fragile, 

 and its colour a faint flesh-tint or yellowish white, 

 slightly dashed with purple. 



In captivity the animal is rather chary of displaying 

 itself; which is the more to be regretted since it is 



kinds, from the minute Turris neglecta upwards, swarmed during the 

 months of August, September, andiOctober, in 1852 ; and it is gene- 

 rally considered that the latter part of summer and autumn is the 

 most favom-able season for studying all the Medusse of our coasts. 



g2 



