MELICERTUM GEORGICUM. 



135 



Melicertum georgicum A. Agass. 



Melicertuni georgicum A. Agass. ; in Agassiz's Cont. Nat. Hist. U. S., IV. p. 349. 1862. 



The Medusa (Fig. 215) is here figured to show the differences no- 

 ticed between it and the New England representative of the genus. 

 The pointed spherosome, the smaller number of the circular tentacles, 

 the longer actinostome, and the termination of the genital organs, 

 somewhat above the circular tube, are characters which readily distin- 

 guish the M. georgicum from its Eastern representative. The knowl- 

 edge of its complete development will settle this point definitely. The 

 close resemblance of the mode of attachment of the ovaries to that 

 of the ^quoridas, referred to in the preceding species, is readily seen 



in Fig. 216. The genital folds are looped up on the upper side of the 

 interior of the bell in an octagonal outline (Fig. 216), opening into the 

 large cavity formed by the eight constrictions of the Hps, I, of the acti- 

 nostome. The difference is simply in the number of the chymiferous 

 tubes, as well as in the mode of carrying the lips of the actinostome. 

 A simple flattening of the spherosome, and an increase in the number 

 of chymiferous tubes, would give us an ^quorea. This Medusa is 

 found, in the summer, in the Gulf of Georgia, W. T. 



Fig. 215. Profile of Melicertum georgicum, natural size. 



Fig. 216. Digestive cavity and point of junction of the chymiferous tubes. I, lips of actinos- 

 tome ; p, abactinal point of attachment of genital organs ; c, opening leading into chymiferous 

 tubes. 



