98 



STOMOBRACHIUM. 



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

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

 development of the chymiferous tubes of Zygodactyla, and the other 

 jEquoridge which I have had occasion to observe. The tubes ai^e 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. 



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

 Sto7nobrachium Less. Zooph. Acal., p. 315. 1843. 

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



Stomobrachium tentaculatura Agass. 



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

 Stomobrachium lenliculare Gould {nan Br.). Rep. Inv. Mass., p. 349. 1841. 

 f 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 



bemg 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. 



