TURRIS VESICAEIA. 



165 



having habits similar to those of Tima, it is only accidentally met 

 with. It has very much the same kind of coloring as our Tima, but 

 in Turris the color of the genital organs and the base of the tenta- 

 cles is somewhat more yellowish. The bell of Turris is exceedmgly 



thin, except at the abactinal pole (Fig. 261), where it forms a sort 

 of bladder, capable of more or less contraction at its base ; when the 

 Medusa is disturbed, the sides of the bell, below the bladder, contract, 

 and give it a polygonal outline, as is seen in Fig. 262. The genital 



organs remind us somewhat of those of Ptychogena, only they are 

 attached to the abactinal part of the interior of the bell ; passing in 



Fig. 261. Turris vesicaria, natural size ; seen in profile. 



Fig. 2G2. The same, with the bell contracted. 



Fig. 263. A portion of the disk, seen from the abactinal pole, a, opening of actinostome ; g, 

 point of attachment of the convoluted genital organs to the inner surface of the bell ; c, chymifer- 

 ous tubes ; c', continuation of convolution of genital organs, forming the sides of the chymiferous 

 tubes. 



Fig. 264. Magnified profile view of genital organs and actinostome. I, lips of actinostome ; 

 g', convoluted genital organs, extending from one side of the bell to the other ; g, part of the geni- 

 tal organ on the other side of the chymiferous tube ; c', as in Fig. 263 ; v, base of bladder sur- 

 mounting the bell. 



