166 



TURRIS VESICARIA. 



deep festoons (Fig. 263) from one cliymiferous tube to another ; they 

 form a compact mass, and fill the whole of the upper part of the bell ; 

 from this are suspended four movable, deeply-frilled lips (/, Fig. 264), 

 leading into a short digestive cavity totally concealed by the genital 

 organs. The cliymiferous tubes are broad and very flat, the two edges 

 of the tubes being irregularly cut (Fig. 265) ; transverse folds extend 

 from one side to the other ; the cliymiferous tubes open into a 

 broad circular tube (Fig. 266), having a similar hacked edge ; with 

 the circular tube communicate five tentacles placed between the chy- 

 miferous tubes, and one opposite each. The tentacles are broad at the 

 base, and taper very rapidly into a long slender lash ; at the base of 



the bag of the tentacles is a large swelling, in the centre of which is 

 placed a distinct eye-speck. (Figs. 266, e ; 267, 268.) The size of 

 the opening, leading from the circular tube to the tentacle, is readily 

 seen when examined from the abactinal side. (Figs. 263 ; o, 268.) 

 In the genera Tunis, Ptychogena, Olindias of Midler, and Polyorchis, 

 we have strongly developed characters, which show their close rela- 

 tion ; in Turris and Ptychogena, the nature of the genital organs and 

 the character of the chymiferous tubes ; in Olindias and Polyorchis, 

 the genital organs and branching tubes, being simply extreme cases 

 of what we have first hinted at in Turris, more strongly marked in 

 Ptychogena, in the mode of attachment of the genital organs, and 



Fig. 265. Magnified view of a part of a chymiferous tube. 



Fig. 266. Ba.se of one of the chymiferous tubes, and part of the circular tube, c, chymiferous 

 tube; c'', circular tube; h, sensitive bulb of tentacle; e, eye-speck; /, lash of the tentacles cov- 

 ered with lasso<'ells. 



Fig. 267. One of the tentacles in a semi-profile view. 



Fig. 268. One of the tentacles, seen from the abactinal pole, o, opening leading from circular 

 tube. 



