[183] THE HYDROIDS 201 



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). 



Sertularia tricuspidata Alder, Catalogue of the Zoophytes of Northumber- 

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



Cotulina tricuspidata A. Agassiz, North American Acalephae, p. 146, 1864. 



Sertularella tricuspidata 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, 



Distribution. — ^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 poly zonias Linn., Systema Naturae, Ed. x, p. 813, 1758. 

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



British 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. 

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



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

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



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



Distribution. — 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 kS. 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- ) 

 Sertularella rugosa Clark, Proc. Acad. Nat. Sci. Phila., p. 224, 1876. 



