618 



MEDUS.E OF THK WOULD. 



niches. The sense-club is covered bv a prominent scale, beneath which it stands in an almost 

 venical position. There is a deep exumbrella sensory-pit above each sense-club. There 

 appear to be no distina velar lappets, the bell-margins being only slightly wavy, excepting tor 

 the deep, rhopalar clefts. In Bigelow's large medusa 41 radial-canals arise from the periphery 

 of the circular central stomach, but two of these anastomose so that only 40 extend to the ring- 

 canal centripetal to the zone of the rhopalia. The ring-canal gives rise to a trident-shaped 

 diverticulum in the radius of each sense-club and to one or two simple, blindly-ending divertic- 

 ula in the inter-rhopalar spaces. The canal-system, like the rhopalia, bears a striking resem- 

 blance to Phaccllophora. The mouth pans appear also to be similar to those of Phacelloplwra 

 but are not well preserved in any specimen \et captured. The gonads form a nearly continuous 

 ring around the periphery of the subumbrella floor of the stomach. This ring is not truly con- 



Fic. 396. — Poralia rufncens, after H. B. Bigt-low, in Mem. Mus. Comp, 

 Zool. at Harvard College. 



tinuous, however, but is interrupted h\ 18 or 19 thickened, vertical ridges in the stomach-wall. 

 The gonads themselves thus consist of 18 or IQ outpocketings of the stomach-wall project- 

 ing outward. The numerous, simple, gastric cirri are arranged in a single line arising from the 

 stomach-wall on the inner side of the genital organs. The subumbrella is reddish-brown, the 

 gonads being paler. The tentacles were lost in all of the specimens so that we know nothing 

 of them. 



Vanhoffen's specimen came from a depth of about ^50 fathoms between Ouecn F^mnia 

 Harbor and Siberut Island, Indian Ocean, and the two described b)- Bigelow were found by 

 the Albatross in the eastern part of the tropical Pacific. 



The radial-canals in this medusa appear to increase in number with growth, for \'anhoffcn's 

 specimen which was only about 60 mm. wide had 21 canals, while Higclow's 250 mm. wide 

 specimen had 41. Vanhiiffen's medusa had 7 or 8 ( ?) gonads, and iioth he and Bigelow believe 

 that the young medusa is probably octoradial. 



Subfamily AURELINiE L. Agassiz, 1862. 



The numerous tentacles and lappets arise from the sides ot the exumbrella above the 

 margin. Gonads are invaginated sacs with external subgenital cavities. 4 simple or bifurcated 

 mouth-arms. 



