118 DISCOPHOR^. Part III. 



ever, readily distinguished by the circumstance that the tentacles arise from the 

 lower floor, and not between the marginal lobes, as is the case in Chrysaora. 



The genus Couthouyia, named Nerinea by Mr. Couthouy, and handsomely illus- 

 trated by him, in unpuljlished drawings, made during the U. S. Exploring Expe- 

 dition, under the command of Capt. Charles Wilkes, is closely allied to Cyanea by 

 its sixteen broad radiating pouches and eight large bunches of tentacles; but it 

 differs in having four distinct, long, pendant arms, like Chrysaora, and in having the 

 tentacles arranged in a single row, as in Sthenonia. The indentations of the margin 

 are also peculiar, and recall, in a measure, those of Phacellophora more than those 

 of Cyanea, the eight bunches of tentacles corresponding to eight prominent mar- 

 ginal lobes, instead of fronting deep indentations, and the ocular lobes being quite 

 distinct from the tentacular lobes; but the essential character in Couthouyia con- 

 sists, as in Cyanea, in the presence of sixteen large radiating pouches, the only 

 distinction between the two genei'a, in this respect, consisting in the great inequality 

 of the eight ocular and the eight tentacular pouches in Cyanea, while in Cou- 

 thouyia they are nearly equal. The genital pouches of Couthouyia are not so 

 extensive as in Cyanea. Only one species of this genus is known, from Orange 

 Harbor, Cape Horn, for which I propose the name of C. pendula, on account of 

 the extraordinary length of the arms. The name Nerina being preoccupied, I 

 have substituted for it that of the discoverer of the species. 



The unpublished genus Medora of Couthouy, which I know from drawings made 

 under the same circumstances as those of the preceding genus, is closely allied to 

 Couthouyia, but differs, however,, in having the margin of the tentacular pouches 

 divided into two broad lobes, like Cyanea, with only one tentacle between them, 

 and one on each side of them. There are representations of two species among the 

 drawings of the U. S. Exploring Expedition, one from Orange Harbor, called Medora 

 reticulata by Mr. Couthouy, the other from the Pacific Ocean, in sight of Cape Horn, 

 called M. capensis by the same naturalist. All these drawings are shortly to be 

 published. 



The position of the genus Patera, of Lesson, in this family, remains doubtful. 

 Lesson having made no mention of the genital pouches in his description, and his 

 plate furnishing no information to supply the deficiency. The extraordinary devel- 

 opment of the actinostome, and the lobation of the margin of the disk, suggest, 

 however, a close affinity with Cyanea ; but the oral appendages form a convolute 

 mass of meandering folds instead of light-flowing curtains, and their main branches 

 terminate in a pinnate lobe. The arrangement of the tentacles is similar to that 

 of Stenoptycha, but there are twice as many. 



The genus Donacostoma has sixteen bunches of tentacles, like Patera, arranged 

 in a single row in each lobe, and as there are only eight eyes, there are, respect- 



