Chap. II. AURELIA FLAVIDULA. 45 



XP. Fig. 3") I), the first of the numerous groups which stud the disk of the full- 

 grown animal. In the next series of figures (PL Xl". Figs. 22 and 32 ; PI. X*. 

 Figs. 37, 39, 40, and 41) we have a more decided advance in development than in 

 the two last. The marginal veil (PL XP. Fig. 22 «') is quite as prominent, if not 

 more so, than the oculiferous lobes (/). The upper margin of the sockets, between 

 the tentacular lobes (see the adult PL VII. Figs. 2, 3, and 4 It), has begun to form, 

 by the projection of a single tongue-like body (PL XP. Fig. 22 /^) from the edge 

 of the disk, directly above the veil (i^) ; and the breadth of each margin is about 

 the same as its length, and corresponds, as regards the latter, to the length of 

 the margin of the disk. The marginal fringes (PL X^ Figs. 37, 39, 40, and 41 a^) 

 of the proboscis have increased considerably in number; but in this respect there 

 would seem to be considerable variation even on the same proboscis (Figs. 39 and 

 40), some of the lobes being entirely destitute of any appendages, whilst others 

 have one or two, or six and seven. The thick, heavy character of the proboscis, 

 as it existed in younger stages, is gone, and in its jik'^ce we have a long, thin- 

 walled, trumpet-like body, folded into four exceedingly flexible lobes. The digitate 

 sexual appendages (PL X\ Fig. 37 e) are quite numerous and very much crowded. 

 The outline of the upper surface of the disk (PL XP. Fig. 22 I) has a peculiar 

 curve, which has not appeared before to any appreciable extent; it is as if the 

 segment of a smaller sphere had been laid upon that of a larger one. By the 

 inspection of Fig. 32 it will be observed that the marginal intervals (/') occupy 

 nearly twice as much of the circumference as the oculiferous lobes (j). 



Although the next phase of development recorded is considerably in advance of 

 the one just described, we do not anticipate any difficulty in tracing the connection 

 between the two. In this ephyra (PL XP. Figs. 18, 10, 13, and 17, and PL XP. 

 Figs. 3 and 4), which, by the way, is a little more than half an inch across, the 

 tentaculiferous margin of the disk is fully twice as long as the space occupied by 

 the oculiferous lobes; there are fourteen tentacles in each segment, and the veil has 

 kept up with the increasing length of the margin; the eight radiating canals, which 

 are opposite to and half way between the sexual organs, are forked from four to six 

 times; the sexual digitate appendages are almost innumerable, and the exterior 

 pouch, immediately below the sexual organs, is proportionately half as deep as in 

 the adult (compare PL IX. Figs. G, 7, 8, and 9) ; and, finally, the fimbriate prolon- 

 gations of the corners of the proboscis reach half way to the mai'gin of the disk. 

 These are the features which constitute the essential difference between this and 

 the last stage of development; and we do not think the difference is so great as 

 it would appear to be at first sight, being, after all, only a matter of degree. 

 In the first place, the disk has not changed in form, but merely increased in size 

 (PL XP. Fig. 18). The veil (Fig. 17 i) is comparatively much narroAver, but stiU 



