214 



PORPIT.E. 



SUBORDER PORPIT^E GOLDF. 



Porpitcc GOLDF. Handb. cler Zool. 1820. 



Porpi/ce and Physalm AGASS. Cont. Nat. Hist. U. S., IV. p. 366. 1862. 



Chondropliorce CHAM, et EYS. Acta Nova, X. 



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

 SiphonophoraB, I have been induced to extend the limits of this sub- 

 order so as to include Physalia, forming thus three suborders among 

 Hydroids of the old order of Siphonophorse, the Diphyce, the Physo- 

 phora?, and the Porpitae. 



Family PHYSALID^E Brandt. 



PhysaUdce BR. ; in Mem. Acad. St. Petcrsb., p. 236. 1835. 

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



PHYSALIA LAMK. 



P1i>imUa LAMK. An. s. Vert., HI. p. 89. Second Edition. 



Arethusa BROWN. Nat. Hist. Jam. 



Arethusa LESS. Zooph. Acal., p. 530. 1843. 



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



Fig 351. 



rnV 



Physalia Arethusa TIL. 



Physalia Arethusa TIL. ; in Krusenst. Reise, PI. 23, Figs. 1-6. 1813. 

 Physalia Arethusa OLF. ; in Mem. Berl. Acad., PL 1. 1832. 

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



PL 35. 1862. 



Physalia pelasoica Bosc. Hist. Nat. d. Vers, II. p. 168. 

 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 young 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 ; &, open end of air-sac ; c, crest of air-sac ; m, bunches 

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

 gest kind expanded. 



