Chap. III. THE GENERA OF CYANEID^. 117 



lobes, each of which has four rounded lobules. In the deeper indentations which 

 separate the sixteen lobes, there are sixteen eyes, a circumstance which leads me 

 to suppose that Phacellophora also has the same number of eyes. Morphologically, 

 the tentacles, which are very large, are arranged in sixteen bunches ; but as their 

 insertion follows the regular curve of the circular chymiferous tube, and does not 

 form a crescent, as in Phacellophora, and as the lappets of the eyes are not sep- 

 arated from the tentacle-bearing lobes, the tentacles seem to form a continuous 

 row along the whole margin, as in Aurelia, instead of assuming the appearance 

 of bunches, as in Phacellophora. 



The affinity of Cyanea with the genus Sthenonia is more remote, even though 

 the indentations of the margin of the disk be more similar to those of Cyanea 

 than those of the genera Phacellophora and Heccoedecoma ; for in Sthenonia, the 

 actinostome consists of four diminutive arms, and the resemblance between the two 

 genera results only from the arrangement of the long slender tentacles, hanging 

 in eight bunches from the lower side of the disk, in the intervals between the 

 oculiferous lobes. The evidence that neither Sthenonia, nor Phacellophora, nor Hec- 

 csedecoma, can be associated in the same family with Cyanea, appears to me chief!}" 

 to rest upon the fact, that while in Cyanea the bunches of tentacles correspond to 

 the deepest indentation in the margin of the disk, in the above-named genera, 

 which I refer to a distinct family, the Sthenonidaj, they correspond to prominent 

 lobes of the margin, and are separated from the lobules of the eyes by deep 

 indentations; and as these outlines are determined by the mode of ramification 

 of the chymiferous system, they must be considered as family characters. 



The true characters of the genus Cyanea consist in the deep indentations of the 

 margin, in the radial prolongation of the l)unches of tentacles, and in the greater 

 width of the lobes of the margin corresponding to the tentacular pouches, while 

 those of the ocular pouches are small and more closely united with the broad lobes 

 than with each other. The crescent-shaped insertion of the bunches of tentacles, 

 arranged in several rows, the largest of which are on the inside, and the smaller 

 outside, is another generic peculiarity. The division of the concentric lobes into 

 alternately broader and narrower contiguous areas, appears also generic, as well as 

 the division of the radiating folds into a shorter and a longer band. 



The other genera which I refer to the family of Cyaneidae are Stenoptycha 

 Ag., based on the Cyanea rosea Q. and G., Couthouyia Ac/., Medora Couth., Patera Less., 

 and Donacostoma A(j. The genus Stenoptycha is unquestionably a member of the 

 family of Cyaneidse, as the concentric and radiating folds of its lower floor show; 

 but in this genus the band of concentric folds is very narrow, and the radiating 

 folds alternate with the concentric folds. The tentacles are few, and arranged in a 

 single row. This genus has some affinities to Chrysaora, from which it is, how- 



