98 



STOMOBRACHIUM. 



than to find specimens having twenty or twenty-two chymiferous tubes, 

 instead of the normal number. The same is the case in the order of 

 development of the chymiferous tubes of Zygodactyla, and the other 

 ^quoridoe which I have had occasion to observe. The tubes are fre- 

 quently added all on one side of the spherosome, and will be nearly 

 fully formed before they begin to be developed in the other half The 

 specimens observed of this species are evidently not full-grown, as the 

 ovaries were but imperfectly developed. 

 Key West, Florida (L. Agassiz). 



STOMOBRACHIUM Brandt. 



Stomohrachium Br. (;non Forbes). Prod. ; in Mem. Acad. St. Petersb., p. 220. 1835. 

 Stomobraclnum Less. Zooph. Acal., p. 315. 1843. 

 Stomohrachium Agass. Cont. Nat. Hist. U. S., IV. p. 361. 1862. 



Stomobracliiuni tentaculatum Agass. 



Stomobrachium tentaculatum Agass. Cout. Nat. Hist. U. S., IV. p. 361. 1862. 

 Stomohrachium lenticulare Gould {non Br.). Rep. Inv. Mass., p. 349. 1841. 

 ? Medusa bimorpha Fab. Fauna Gronlandica, No. 356. 1781. 



This species is occasionally found at Nahant during July. It has 

 twelve chymiferous tubes, a small digestive cavity, the folds of the acti- 

 nostome hanging down in four lobes, placed at right angles to one 

 another; these lobes are triangular (Fig. 140), the apex of the triangle 



Fig. 141. 



Fig. 140. 



being placed nearer the origin of the chymiferous tubes ; the edges 

 are frilled ; the trend of the triangles is in the direction of four of 

 the chymiferous tubes. Between each two of the chymiferous tubes 

 (Fig. 141) there are from thirty to forty tentacles, in all stages of 



Fig. 140. The actinostome of Stomobrachium tentaculatum, magnified to show the peculiar 

 mode of carrying the folds of the digestive cavity. 



Fig. 141. Stomobrachium tentaculatum, seen from the abactinal pole ; natural size. 



