36 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 4 



even slightly backward in the distal portion; two or three annulations 

 at the base of each internode; pedicels, except the terminal one that is 

 annulated at each end, are annulated throughout. Hydrotheca small, 

 broadly campanulate, slightly flaring at the margin, which is supplied 

 with 10 rounded, comparatively shallow teeth. 



Gonosome. — Gonangia arising from the axils of the hydrothecal 

 pedicels, obovate, with a terminal opening but without a definite collar. 



Distribution. — Post Office Bay, 12-15 fathoms; west of South Sey- 

 mour Island, 5 fathoms. 



This species resembles O. dichotoma in its mode of growth, but the 

 colonies are, in general, much smaller, and the hydrothecae are quite 

 dissimilar. 



Obelia articulata (A. Agassiz) 



Eucope articulata A. Agassiz, N. A. Acalephae, 1865, p. 89. 



Obelia articulata Fraser, Hyd. of Eastern Canada, 1918, p. 348. 



Distribution. — Between Charles and Indefatigable islands, 60 fath- 

 oms. 



Obelia commissuralis McCrady 



Obelia commissuralis McCrady, Gymno. Charleston Har., 1859, p. 95. 



Nutting, American Hyd., Part III, 1915, p. 83. 



Distribution. — Bahia Honda, 15-25 fathoms; Tangola-Tangola, 15- 

 20 fathoms. 



Obelia dichotoma (Linn.) 



Sertularia dichotoma Linnaeus, Syst. Nat., 1758, p. 812. 



Obelia dichotoma Hincks, Br. Hyd. Zoophj^tes, 1868, p. 156. 



Distribution. — Tagus Cove, on coral and sponges at low tide ; Santa 

 Elena Bay, on drifting Sargassum; Tangola-Tangola, 15-20 fathoms; 

 north of White Friars, 25 fathoms; east of islands off Navidad Head, 

 25-35 fathoms. 



Obelia equilateralis, new species 

 Plate 9, Fig. 39 



Trophosome. — Colony small, simple, unbranched, reaching a height 

 of 6 or 7 mm. Stem irregularly geniculate, annulated at the proximal 

 end of the internodes. Hydrothecae irregularly arranged on long pedi- 



