202 NUTTING [184] 



Sertulareila geniculata Marktanner-Turneretscher, Die Hydroiden Des 

 k. k. naturhistorischen Hofmuseums, p. 222, 1890. 



Trophosome. — Colony consisting of a sparingly branched, non- 

 fascicled stem attaining a height of about one inch. Stem annulated 

 and nonhydrothecate proximally, otherwise bearing alternate hydro- 

 thecae, one to each internode ; stems and branches erect. Hydrothecae 

 roughly ovate in general outline, with a laterally inclined, broad, 

 smooth, round neck or collar surmounted by a four-toothed aperture 

 and a four-flapped operculum ; below the neck the body of the hydro- 

 theca has three or four broad annular corrugations. Hydranths with 

 about sixteen tentacles. 



Gonosome. — Gonangia large, oblong-ovate in general outline, with 

 several, seven to nine, broad annular corrugations. The mature ova 

 are enclosed in an ovoid acrocyst resting on the top of the gonangium. 



Distribution. — Popof Island, Alaska (Harriman Exped.) ; Un- 

 alaska, Shumagin Islands, St. Paul Island and Nunivak Island, Alaska 

 (Clark) ; Jan Mayen (Marktanner-Turneretscher). 



The specimens of this species secured by the Harriman Expedition 

 agree well with the figure given by Clark of specimens that he identi- 

 fied as 5". rugosa. The very conspicuous neck, however, w^ould seem 

 to be sufficient to distinguish S. saccata from S. rugosa., and the same 

 difference exists between the gonangia of the two forms. The figure 

 given by Marktanner-Turneretscher for S. geniculata Hincks differs 

 greatly from Hincks's original description and figure, and agrees well 

 with the present species, except that the hydrothecae are more closely 

 approximated in the latter. 



THUIARIA. 



Trophosome. — Colony branched, the branches divided into unequal 

 internodes, each bearing several pairs of opposite or subopposite hy- 

 drothecae. Hydrothecae usually deeply immersed in the stem or branch 

 to which they are attached. The branches are alternate, and each 

 springs from an unpaired hydrotheca. 



Gonosome. — ^Much as in Sertularia. 



THUIARIA ARGENTEA (Ellis and Solander). 



Sertularia argentea Ellis and Solander, The Natural History of many curious 

 and uncommon Zoophytes, etc., p. 38, 1786. — Clark, Hydroids of the 

 Pacific Coast of the United States south of Vancouver Island, Trans. 

 Conn. Acad., Vol. iii, p. 251, 1876. — Verrill, Preliminary Check-list 

 Marine Invertebrates Atlantic Coast, etc., p. 18, 1879. — Bergh, Gople- 

 polyper (Hydroider) fra Kara-Havet, p. 335, 1887. — Nutting. Hydroida 

 from Alaska and Puget Sound, Proc. U. S. Nat. Mus., Vol. xxi, p. 741, 

 1899. 



