200 PHYSOPHOR^. 



Suborder PHYSOPHORiE Goldf. 



PhjsophorCE Goldf. Handb. d. Zool. 1820. 



PliysojihorcE Agass. Cont. Nat. Hist. U. S., IV. p. 3G7. 1862. 



Family AGALMIDiE Brandt. 



Agalmidce Brandt ; in Mem. Acad. St. Petersburg, p. 234. 1838. 

 Agalmce Less. Zooph. Acal., p. 509. 1843. 

 StepJianomice Less. Zooph. Acal., p. 475. 1843. 

 Stephanomidoe Leuck. ; in Ai-chiv f. Nat., L p. 312. 1854. 

 Stephanomidm HuxL. Ocean. Hyd., p. 72. 18.58. 

 Agalmidce Agass. Cont. Nat. Hist. U. S., IV. p. 3G8. 1862. 



NANOMIA A. Agass. 



Nanomia A. Agass.; in Proc. Boston Soc. Nat. Hist., IX. p. 181. 1863. 



Nanomia cara A. Agass. 



Nanomia cara A. Agass. ; in Proc. Bost. Soc. Nat. Hist., IX. p. 181. 1863. 



This Siphonophore is closely allied to the genus Agalmopsis of Sars, 

 but the nature of the tentacles of the feeding polyps, and the mode of 

 arrangement of the swimming-bells, show undoubtedly that it cannot 

 be placed in the same genus as Agalmopsis, though closely related to 

 it, as also to Halistemma of Huxley. The small size of this species has 

 been of great advantage in enabling us to seize readily, at one glance, 

 the connection between the difierent parts of this community, whde 

 the great size of many of the species hitherto observed has always been 

 more or less of a drawback in analyzing the relations of the individuals 

 of the community. 



Fis.331. The float, or swimming-bladder, (I shall use at present 



the nomenclature usually adopted, and afterwards show to 

 what parts these organs correspond in an ordinary Hy- 

 droid,) is a large elliptical cavity (Fig. 331), entirely shut 

 off from the main cavity, which runs from the base of the 

 float, through the whole of the axis of the community. It 

 contains in this genus a bubble of oily substance ; the na- 

 ture of the contents of the float varies in different families 

 of Siphonophorae, and this cavity may or may not be closed. In this 

 genus it is closed, and there is no access to the oil-bubble from with- 

 out ; the oil-bubble by no means fills the whole of the . cavity of the 

 float. The float is of a brilhant garnet color ; from it hangs the rosy- 

 Fig. 331. Oil-float of Nanomia; magnified. 



