198 



HYDRACTINID^. 



Family HYDRACTINIDiE Agass. 



Hydractinidm Agass. Cont. Nat. Hist. U. S., IV. p. 339. 1862. 



HYDRACTINIA Van Beneden. 



Hydractinia Van Beneden ; in Bull. Acad. Bel., VIII. 

 Hydractinia Agass. Cont. Nat. Hist. U. S., IV. p. 339. 

 Synhydra Quat. ; in Ann. des Scien. Nat., XX. p. 230. 



1841. 

 1862. 

 1843. 



Hydractinia polyclina Agass. 



Hydractinia polyclina Agass. Cont. Nat. Hist. U. S., HI. PI. 16 ; IV. pp. 227-239, 339, Figs. 



33-35; PI. 26, Fig. 18. 1862. 

 Hydra squaniata Fab. Fauna Gronlandica. No. 338. 

 Alcyonium echinatum Gould. Rep. Inv. Mass., p. 351. 



Hydractinia echinata Leidy. Mar. Inv. New Jersey and Rhode Island, p. 3, PI. X. Fig. 35. 1855- 

 Hydractinia echinata Stimps. Mar. Inv. Grand Manan, p. 11. 1853. 

 Hydractinia echinata McCr. Gymn. Charleston Harbor, p. 66. 

 Clava squamata Morch ; in Beskriv. af Gronland, p. 96. 

 Hydractinia polyclina Pack.; in Can. Nat. & Geol. Dec. 1863. 



As such constant reference is made to Hydractinia in the comparison 

 of the free colonies of Nanomia to the fixed Hydroids, figures of male 



Fig. 329. 



Fig. 330. 



(Fig. 329) and female (Fig. 330) colonies of this species are here intro- 

 duced to facilitate the comparison. 



Point Judith (Leidy) ; Atlantic coast of North America (L. Agassiz). 



Cat. No. 55, Grand Manan, 1859, A. E. Verrill. 



Cat. No. 56, Grand Manan, October, 1857, J. E. Mills. 



Cat. No. 57, Chelsea Beach, L. Agassiz. 



Cat. No. 58, Swampscott, Mass., March, 1859, S. Tufts. 



Cat. No. 59, Nantucket Shoals, July, 1849, L. Agassiz. 



Cat. No. 403, Nahant, Mass., July, 1862, A. Agassiz. 



Museum Diagram, No. 25, after L. Agassiz. 



Fig. 329. Part of male community of Hydractinia. a, a, sterile individuals ; b, fertile indi- 

 vidual ; d, male Medusa^ ; o, o, proboscis ; t, elongated tentacle of sterile individuals. 



Fig. 330. Part of female community, a, sterile individual ; b, fertile individual, producing 

 female Medusaj, d, e, f, g, h, i ; o, peduncle of mouth ; c, individual with globular tentacles. 



