110 



iEQUOREA ALBIDA. 



^quorea albida A. Agass. 



^quorea albida A. Agass. ; in Agassiz's Cont. Nat. Hist. U. S., IV. p. 359. 18G2. 



The genus -^quorea, as generally received, includes species which 

 have been separated from it, iinder the name of Zygodactyla, by 

 Brandt, and to which the jEquorea vitrina of Gosse also belongs. The 

 long pendent membrane of the digestive cavity, with the actinostome 

 Fig 160. surrounded with numerous lanceolate and strongly 



fimbriated folds, at once distinguishes this genus 

 from Rhegmatodes, which includes such sj^ecies as 

 Hhegmatodes tenuis mid floridcmits, and the ^quorea 

 forhesiana of Gosse, in which the chymiferous tubes 

 are not numerous, the tentacles few in number, and 

 the digestive cavity not capable of extension as in 

 Zygodactyla, the lips of the actinostome being short 

 and simple folds, -^quorea is distinguished from 

 both these genera by having a greater number of 

 chymiferous tubes, the ovaries extending for their 

 whole length, from the circular tube to the mem- 

 brane of the digestive cavity. The tentacles are nvimerous, the spurs 

 at the base of the large tentacles being more closely connected with 

 them than in the other genera of this family. The actinostome is a 

 simple opening, without appendages such as we find in Zygodactyla, 

 Stomobrachium, and others, having only slight indentations formed 

 along its margin, giving the opening a somewhat polygonal shape 

 Pig. 161. (Fig. 160) ; and when entirely 



closed, the edges of the acti- 

 nostome meet, forming a shght 

 button. The spherosome has a 

 slight indentation near the ab- 

 actinal pole, the bell diminish- 

 ing very gradually in thickness 

 towards the circular tube (Fig. 

 161) ; the gelatinous disk hardly 

 projects into the cavity of the 

 bell ; the chymiferous tubes run 

 into the digestive cavity at 

 their highest point, the radius 

 of the digestive cavity being about one third that of the spherosome ; 

 the chymiferous tubes are narrow, there are three or four marginal 

 tentacles between every two chymiferous tubes, and two or three 



Fig. 160. A portion of tlie disk of ^quorea albida, from the abactinal pole. 

 Fig. 161. A natural attitude of .lEquorea albida. 



