WEST COAST HYDKOIDS 45 



count, and because it has not been reported previous to this time 

 from the Pacific Coast, it might be well to give here the substance 

 of Sars' general description from the tj'pe specimen. 



Polyps always growing from an irregularly branched stolon^ 

 ■which firmh' adheres to some foreign support. From this sup- 

 port the numerous pedicellate hydrothecae radiate in all direc- 

 tions, often quite densely aggregated. The sub-erect pedicels,, 

 slightly annulated at the base, vary much in length, some of them 

 being quite long. They pass almost imperceptibly into the tubu- 

 lar somewhat obconic hydrothecfe, the apertures of which are 

 circular. The operculum consists of about twelve converging 

 segments, which may be extended above the rim of the hydro- 

 theca, or be retracted within it. The portion of the hydrotheca 

 near the margin may be slightly ribbed longitudinally. 



Gonosome unknown. Color, grayish-white. Height of the hy- 

 drotheca with pedicel up to 6 mm. Found attached to the stems 

 of Tuhularia indivisa and to calcareous serpulid tubes. 



The specimens I have examined answer to this description very 

 well, except that the pedicels are not so long. According to Sars' 

 figures, in his specimens the variation is from 2 mm. to 6 mm. 

 In specimens from Dodd's Narrows the longest is not more than 

 2 mm., and in the San Juan material many of them are little more 

 than 1 mm., but as they agree in every other respect, I do not hesi- 

 tate to put them with this species. 



Genus STEGOPOMA 



Trophosome. — Hydrotheca with an operculum formed of two 

 membranes, folded lengthwise, and which, roof-like, come to- 

 gether with their long edges. Each of these is separated from 

 the remainder of the hydrotheca by a curved line. At each side^ 

 the hydrothecal wall forms a triangular gable-like structure be- 

 tween the two opercular membranes. 



I have not seen specimens of this genus. Levinsen in institut- 

 ing the genus gives no characters of the gonosome." Later 

 authors who have used the genus, have described the gonangia in 

 some species but have not described the contents thereof. 

 STEGOPOMA PLICATILE (Sars) 



Lafoca plicatile Saks, Vidensk. Selsk. Forhandl., 1862, p. 31. 

 Stegopoma plicatile Levinsex, Meduser. Ctenophorer og Hydroider, 1893. 

 p. 3G. 



1' Meduser, Ctenophorer og Hvdroider fra Groenlands Vestkyst, 1893, p. 34. 



