MELICERTUM CAMPANULA. 



133 



stage (Fig. 205), whicli is undoubtedly a young Melicertura, we find 

 the second set of four chymiferous tubes developing (2„, Fig. 205) ; 

 they arise, as in the JEquoridte, from the digestive cavity, and extend 

 towards the circular tube ; there are at this stage sixteen tentacles, 

 usually carried curled up, as in the accompanying figure. I have not 

 seen the young Melicertum in stages intermediate between those 

 slightly more advanced than Fig. 205, and when they are fully devel- 

 oped, as in Fig. 202, where the genital organs extend to the circular 

 tube, and the marginal tentacles have become exceedingly numerous. 



Fig. 206. Fig. 207. 



The spherosome is regularly bell-shaped ; it is capable of very varied 

 expansion and contraction, appearing at some times almost rectangular, 

 then as if tied in the middle, swelling at both poles, again flaring at 

 the abactinal extremity, and strongly contracted at the circular tube, 

 or flattened like a quoit. The tentacles may expand several times the 

 polar diameter of the bell, or contract, by curling close to the circular 

 tube. The bell is of a light ochre color ; the genital organs, as well 

 as the base of the tentacles, are of a darker shade. When seen from 

 above (as Fig. 206), the radiating tubes open Fig. 209. 



into a sort of cavity, as in the ^Equoridge, the 

 folds of one genital organ extending across to the 

 next, as seen in Figs. 207, 208 ; the ovaries are 

 convoluted (Fig. 207), extending from I, Fij"- 

 207, to the circular tube, where they have thei 

 greatest diameter ; the lips of the actinostom 

 are carried in eight folds (Fig. 208), each one, / 

 corresponding to one of the radiating tubes, > 

 as in the ^quoridse ; the lips project but littl 

 into the cavity of the bell. The tentacles ar 

 hollow, somewhat dumb-bell shaped at the base 



Fig. 206. Tlie same, seen from the abactinal pole, m, mouth ; o, genital organs ; ?, tentacles. 



Fig. 207. Magnified vie-w of two chymiferous tubes and genital glands, l, lips of actinostome. 



Fig. 208. Mode of carrying the lips of the actinostome. I, lips of actinostome ; c, chymiferous 

 tube. 



Fig. 209. Magnified view of marginal tentacles. 



