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PROCEEDINGS OF THE 



[April, 1857. 



in the periphery of the digestive cavity, where there are usually 

 broad diverticula of that cavity for their reception. The muscu- 

 lar portion of the bell is represented by a narrow circle of lobes 

 around the digestive cavity, to which on their lower margins is 

 attached the vail which is very distinctly developed. There are 

 no ocelli, but concretionary capsules exist in profusion and in 

 very variable number. The tentacula are in comparison to those 

 of most Hydroidea, stiff and wanting in contractility. 



The development is known in Aeginopsis mediterranean and the 

 species of Cunina described below. We should probably also in- 

 clude here the development of Stenogaster complanatus, (Kolliker.) 

 The polyp is directly metamorphosed into the Medusa, though 

 multiplication by budding goes on during the metamorphosis in 

 Cunina. In the cases of Cunina and Stenogaster, the larva lives 

 as a parasite in the cavity of another Medusa's bell. 



The type of this family is synthetic. It belongs to the Hydroidea, 

 but it has analogies which ought not to be overlooked with the 

 Discophorae, in the broad imbedded digestive cavity, the position 

 of the sexual organs, and the frequently pendent and slashed 

 vail. Indeed, it is impossible sometimes to avoid being struck 

 with the resemblance between a Cunina and some forms of Ephyra. 



CUNINA Eseh. 



Disk more or less broad and low. Tentacula placed each at the 

 end of one of the diverticula from the stomach. Every other char- 

 acter in this genus as at present circumscribed is inconstant. The 

 diverticula, tentacula and concretionary capsules, vary In number 

 among the species. The form of the diverticulum varies from 

 that of a broad tube ((7. vitrea Gegenb.) to a subquadrate form, 

 which is more usual. Gegenbaur mentions that the broad vail is 

 perforated by several canals which originate in the diverticula of 

 the stomach and end blindly near the margin of the vail. This 

 would constitute a still nearer approach to the Hooded-eyed Me- 

 dusae. I saw nothing of this kind in the species about to be de- 

 scribed. Larva, a free hydra, like the free stage of the Tubularia; 

 embryo moving about by its tentacula. The stem end of the body 

 flat — the oral prolonged into a siphon-like appendage, terminated 

 by the mouth. Development a homogony. The larva is para- 

 sitic. 



