104 DISCOPHORiE. Part III. 



seen from the outside, and PI. V^ Fig. 14, seen from the inside. The pillars them- 

 selves, PL IV. Fi(/. 2 11, and PI. Y". Fig. 15 1, are also a simple prolongation of 

 the lower floor, only that the gelatinous substance, between its outer, and inner 

 layer, is so thickened as to form solid columns between adjoining genital pouches, 

 attached to the margin of the broad concentric areas of folds, which are imme- 

 diately adjoining the ambulacral areas of concentric folds facing the intervals between 

 the two adjoining arms of the pillars. As these pillars are themselves connected 

 with one another, at the corners of the so-called mouth, by similar thick beams 

 of gelatinous mass, trending horizontally, while the pillars trend radiatingly, the 

 genital pouches are surrounded, from three sides, by these thickened portions of 

 the lower floor; sideways, by the 2)illars {1 1), as best seen in PI. V^ Fig. 15, 

 and PI. IV. Fig. 2, near the mouth, by the transverse beams 8 4, and outside, by 

 the radiating folds, which may be seen gradually fading into the outer surface of 

 the pouches themselves. Owing to the extraordinary amplitude of the genital 

 pouches, which are much wider than the outline of their attachment, their walls 

 are thrown into innumerable folds, gathered into fewer bunches, as may be seen 

 PI. IV. Figs. 1 and 2, and PI. V". Figs. 15, 18, and 19. In a transverse section 

 of the whole animal, as seen in PI. V". Fig. 14, we look directly, in the centre of 

 the figure, into the cavity of one of these pouches, where the attachment of its 

 margin to the concentric folds and to the pillars of the actinostome and the hori- 

 zontal beam which connects them, is plainly visible ; while right and left of it two 

 other genital pouches, opjDOsite one another, are seen in profile. The essential 

 difference between the genital jjouches of Cyanea and Aurelia consists in the even 

 thickness of the loAver floor, over the whole of its extent occupied by the pouches; 

 while in Aurelia the lower floor thickens around the genital pouches, and its thick- 

 ened portions converge from all sides, so as to form a funnel-shaped cavity below 

 the genital pouches, Avhich remain stretched on a level with the spread of the 

 disk ; while in Cyanea, they hang down like large sacks, floating between the 

 bunches of tentacles and the flowing curtains of the actinostome, as may be seen 

 in PL III. and in PL V^ Fig. 14. 



In order the better to apjjreciate the relations of the sexual organs to the 

 genital pouches to which they are attached, one of them (PL V\ Fig. 18) has been 

 represented as separated from the other parts of the lower floor, in such a position 

 as to show the interior of its cavity; o s being the folds attached to a transverse 

 beam of the actinostome, while the semicircular outline is the margin connected 

 with the pillars of the actinostome and with the concentric folds. The lobes on 

 the outside, o f, are the result of the folding of the sexual organ itself, forming 

 small sacs, arranged in undulating lobes, alternately turned in opposite directions. 

 Fig. 19 represents a portion of the pouch, showing its connection with the con- 



