CUNINA PEREGRINA. 61 



broadly open. The gastric pockets are about as broad as long, and nearly 

 square in outline, as is to be seen in the photograph reproduced in 

 ri. 1, fig. 6. 



The most interesting feature of this species, and the one which serves to 

 distinguish it from all larffe species of Cunina previously described, is that it 

 entirely lacks any trace of a peripheral canal system. From a surface view 

 it might well seem that a festoon canal was present (PI. 1, fig. 6) ; but the 

 structure which causes this appearance is in reality not a canal, but the very 

 prominent marginal urticating ring. This I was able to demonstrate on 

 series of sections of the marginal lappets. 



Only two specimens, one a male, the other a female, were approaching 

 sexual maturity. In the male, in which the spermatozoa are nearly ripe, 

 the sexual products form ridge-like thickenings of the subumbral gastric wall 

 along the margins of the gastric pockets, there being no trace of their devel- 

 opment in other portions of the floor of the stomach (PI. 28, fig. J,). On the 

 different pockets these ridges are variously subdivided. In cross section the 

 sharp separation between the ridge, consisting of various generations of male 

 sex cells, and the remainder of the gastric wall is very striking. The female 

 above mentioned is less mature. In this specimen the developing eggs, 

 instead of occupying such a restricted region, form a uniform thickening 

 over the whole surface of the gastric j^ockets. Thus in the males and 

 females of this species the gonads differ in form and location. 



Another interesting anatomical feature of this Medusa is the extremely 

 powerful musculature of the subumbrellar surface of the lappet region. 

 Probably associated with this muscular development is the fact that this 

 is a very active Medusa, swimming with strong pulsations of the bell and much 

 more rapidly than any other Narcomedusa which I have observed alive. 



All the specimens were entirely colorless. 



A very young specimen of this species, measuring only 2 mm. in diam- 

 eter, was taken on the surface at Station 4588. The bell is flat and disc-like, 

 the gelatinous substance very thin, and the marginal zone hardly if at all 

 recurved. In general appearance and in the number of tentacles (8), it 

 closely resembles early stages in the development of Cunodantha odonaria 

 as figured by Brooks ('86, pi. 44, fig. 3). The marginal lobes are much 

 shorter than in the adult, and the incisions between them extend almost to 

 the bases of the tentacles, so that the peroniae can as yet hardly be distin- 

 guished. Nematocyst pads are already developed below the bases of the 



