Chap. III. GROWTH OF CYANEA. 109 



SECTION IV, 



GROWTH OF CYANEA. 



There must be something peculiar in the habits of the young CyanejB to render 

 them, ajjparently, so rare, when, in the adult state, they are so common along our 

 coast. I suppose that during the early stages of their existence they remain near 

 the bottom of the water, as they are very seldom seen floating near the surface. 

 During the many years I have been watching for our Acalephs, I have only on 

 three occasions seen specimens measuring less than an inch in diameter; though, 

 as stated in a former chaj^ter, I have had ample opportunities of tracing some of 

 the first stages of their development, in the egg and in the scyphostoma state. 

 The youngest free Cyanea arctica seen along our shore was observed by my son 

 in Buzzard's Bay ; it measured about half an inch in diameter, and the outline 

 of the disk was very similar to that of a common ephyra of Aurelia, as repre- 

 sented in PI. XI". Fig. 28 ; but the actinostome was already very large in pro- 

 portion to the diameter of the animal. Its four lobes hung like waving curtains, 

 but were still quite distinct one from the other, their lobes being but imperfectly 

 developed. When extended, they reached to twice the length of the diameter. 

 The tentacular pouches were still comparatively small, and from each of their cres- 

 cent-shaped folds hung only six tentacles, two of which were already very long, 

 extending to double the length of the actinostome, or about four times the diam- 

 eter of the disk. The other four were still very short, extending but slightly 

 beyond the outlines of the disk. No trace of the sexual organs was yet visible, 

 but the color of the disk was already similar to that of the adult, only lighter. 

 In other sjiecies of the genus, which I had an opportunity of observing in a some- 

 what more advanced state, the tentacles appeared more nvnnerous, though only a 

 few had grown large : for instance, in specimens of Cyanea versicolor, of South 

 Carolina, measuring an inch and a half in diameter, three tentacles aj^peared larger 

 than all the others, and the genital pouches, though circumscribed between the 

 pillars of the actinostome and the concentric folds of the lower floor, did not yet 

 hang down as pendant pouches. In specimens of a third species, Cyanea fulva, 

 from Long Island Sound, measuring already over two inches in diameter, the genital 

 pouches were still stretched in the same plane as the lower floor, and, though the 

 tentacles projecting from the broad pouches were already numerous, and began to 

 appear in several rows, there were only four in each bunch which hung beyond 

 the actinostome, as in the adult. 



