THE HYDROIDS 183 



alternate, borne on opposite sides of the stem and branches. Margin 

 usually more or less toothed, aperture usually provided with an oper- 

 culum consisting of more than one segment. 



SERTULARELLA TRICUSPIDATA (Alder). 



Sertidaria tricusptdata Alder, Catalogue of the Zoophytes of Northumber- 

 land and Durham, Trans. Tyneside Naturalists' Field Club, p. 21, 1857. 



Cotuiina tricnspidata A. Agassiz, North American Acalephae, p. 146, 1864. 



Serttdarella tricnspidata Clark, Proc. Acad. Nat. Sciences Phila. , p. 224, 

 1876. — Marktanner-Turneretscher, Hydroiden von Ost-Spitzbergen, 

 p. 425, 1895. — Nutting, Hydroida from Alaska and Puget Sound, Proc. 

 U. S. Nat. Mus., Vol. xxi, p. 741, 1899. 



Distribtttion. — Juneau, Berg Inlet, and Yakutat, Alaska (Harri- 

 man Exped.) ; Shumagin Islands, Semidi Islands, Unalaska, Port 

 Etches, and Kiska Harbor, Alaska (Clark) ; British Coast (Alder) ; 

 New England Coast (A. Agassiz) ; Greenland (Marktanner-Turner- 

 etscher) ; Puget Sound (Nutting). 



SERTULARELLA POLYZONIAS (Linn.). 



Sertularia polyzonias Linn., Systema NaturcC, Ed. x, p. 813, 1758. 

 Serttilarella polyzonias Gray, List of the Specimens of British Animals in the 



Bridsh Museum, part i, Radiata, London, 1847. — Sars, Bidrag til Kunds- 



kaben om Norges Hydroider, p. 44, 1873. — Clark, Proc. Acad. Nat. Sci. 



Phila., p. 224, 1876. 

 Cotuiina polyzonias Agassiz, Contributions to the Natural History of the United 



States, Vol. iv, p. 356, 1864. 

 Serttdarella conica Calkins, Some Hydroids from Puget Sound, Proc. Boston 



Soc. Nat. Hist., Vol. xxviii, p. 359, 1899. 



Distributioiz. — Orca, Alaska (Harriman Exped.) ; Port Etches and 

 Nunivak Island, Alaska (Clark) ; British Coasts (Gray) ; North 

 Cape, Norway (Sars) ; New England Coast (Agassiz) ; Puget Sound 

 (Calkins). 



Calkins, in the reference cited above, identifies a small specimen 

 otherwise identical with S. polyzonias^ as the species S. conica All- 

 man, and says : "The only character, and that a small one, by which 

 to distinguish it from the very wide-spread S. polyzonias is the well- 

 marked wrinkling on the adcauline side of the hydrotheca." Speci- 

 mens from Alaska in the Harriman Collection, agreeing with Calkins's 

 description and figures, have the characteristic gonosome of 6". poly- 

 zonias^ and I therefore consider that I am justified in regarding his 

 specimen as belonging to that species. 



SERTULARELLA SACCATA sp. nov. 

 (Plate XXIV, figs. 1-3.) 

 Serttdarella mimosa Clark, Proc. Acad. Nat. Sci. Phila,, p. 224, 1876. 



