214 



PORPITiE. 



Suborder PORPIT^ Goldf. 



Porpiiw GoLDP. Ilandb. dcrZool. 1820. 



Porpitm and Phjaalke Agass. Cont. Nat. Hist. U. S., IV. p. 366. 1862. 



ChondropJiorcE Cham, et Eys. Acta Nova, X. 



From a comparison of the young stages of Nanomia with the known 

 Siphonophora^, I have been mduced to extend the hmits of this sub- 

 order so as to inckide Physaha, forming thus three suborders among 

 Hydroids of the old order of Siphonophorce, the Diphyae, the Physo- 

 phora^, and the Porpitre. 



Family PHYSALID^ Brandt. 



Ph/salidw Br. ; in Mem. Acad. St. Petersb., p. 236. 1835. 

 Physalidce Agass. Cont. Nat. Hist. U. S., IV. p. 366. 1862. 



PHYSALIA Lamk. 



Phjsalia Lamk. An. s. Vert., IH. p. 89. Second Edition. 



Arethusa Bro-svn. Nat. Hist. Jam. 



AretJtusa Less. Zooph. Acal., p. 530. 1843. 



Physalia Agass. Cont. Nat. Hist. U. S., IV. pp. 335, 366. 1862. 



Physalia Arethusa Til. 



Ph/mlia Arethusa Til. ; in Krusenst. Keise, PI. 23, Figs. 1 -6. 1813. 

 P/ii/salia Arethusa Olf. ; in Mem. Berl. Acad., PI. 1. 1832. 

 Physalia Arethusa Agass. Cont. Nat. Hist. U. S., IV. pp. 335, 367, 



PI. 35. 1862. 

 Phjsalia pelasgica Bosc. Hist. Nat. d. Vers, H. p. 1 68. 

 Physalia aurigera McCr. Gymn. Charleston Harbor, p. 74. 



Physalia Arethusa (Fig. 351) is probably carried 

 by the Gulf Stream as far as the Azores. A spe- 

 cies has been described by Lesson as Physalia 

 azoricum, which may be only the yomig of Phy- 

 salia Arethusa. (See Voyage de la Coquille, Plate 

 5, Fig. 4.) To facilitate the comparison of the 

 different kinds of individuals found in communi- 

 ties of this family with those of Nanomia, groups 



Fig. 351. Physalia Arethusa Til. Figs. 351-354 are copied from 

 Professor Agassiz's Contributions, a, blunt end of air-sac supporting 

 the community ; b, open end of air-sac ; c, crest of air-sac ; m, bunches 

 of single individuals ; n, tentacle contracted ; i, t, tentacles of the lar- 

 gest kind expanded. 



