Chap. III. ACTINAL SYSTEM OF CYANBA. 105 



centric folds, in their natural relation, 1}ut seen from the internal surface of the 

 genital sacs. Fig. 20 exhibits a small portion of a lobe magnified, in order to 

 show how the tentacles of the genital pouches are scattered on a broad band, 

 immediately adjoining the folds of the sexual organ, in which the eggs may be 

 seen projecting from the surface of the ovarian lobes. In a younger specimen, 

 Fi(j. 21, the ovaries are not yet fully developed, and the eggs do not project 

 beyond the folds of the ovarian lobes. Fig. 22 represents the male organ, which, 

 even in its mature condition, resembles more, by the form of its lobes, the ovaries 

 of the young, than those of the adult; in o s the connection of the concentric 

 folds with the genital pouch (s) is exhibited. In the male the tentacles of the 

 genital pouches are less numerous than in the females, in their adult condition. 

 The young female has, also, fewer than the adult. 



Considered as a whole, the genital pouches, with their festoon-like lobes of 

 sexual organs, winding in elegant folds around the whole sac, as shown in Fig. 18, 

 have nothing of the rigidity which that figure seems to exhibit ; for it is in 

 unceasing motion, the sac itself being highly contractile. Not only does it wave 

 constantly to and fro, but the folds, into which the whole is drawn, are alternately 

 contracting and elongating, and in these movements the single lobes of the sexual 

 organs are unceasingly changing their relative position. It is only in younger 

 specimens, in which these lobes are comparatively few, as seen in Fig. 18, that 

 their regular arrangement may be traced ; the pouch itself being then shallow and 

 projecting but slightly. As it grows larger the number of folds increases (PI. IV. 

 Fig. 2, PI. V". Fig. 14), and even in specimens of moderate size, as those repre- 

 sented in PI. IV. Fig. 1, and PI. V\ Fig. 15, they are so numerous tha^t their 

 connection may easily escape observation. In very old specimens, in which the 

 genital pouches hang down upon the curtains of the actinostome (PI. III.), these 

 folds are innumerable, and their ])\ay presents a most striking spectacle. These 

 movements seem to be a provision to bring the sexual organs constantly into 

 renewed contact with fresh surfaces of water, and the tentacles, arranged in broad 

 bands along the sexual organs, which are also unceasingly playing in their imme- 

 diate vicinity, must powerfully contribute to this result. 



When the eggs are mature, they drop from the ovarian folds and fall into the 

 genital pouches, and are certainly not cast into the surrounding element, in the 

 normal condition of these organs ; for eggs are always found, at the time of 

 spawning, in innumerable quantity, ujjon the inner surface of the actinostome, be- 

 tween its folds, which, though not provided with little sacks for their reception, as 

 in Aurelia, are, nevertheless, adapted to lodge them between their phcations, and 

 to retain them until they are so far advanced in their transformation, as to be 

 fit to live in open water. Even stranded specimens may frequently be found upon 



VOL. IV. 14 



