350 



Bt T I.I,FTIN OF THK 1 T N T ITED STATES FISH COMMISSION. 



Obelia fiabellata (Hinrks). Fig. :::>. 



iiaiiiilnrMjIiilitllitta Ilincks.. Ann. mid Mag. Nat. Hist., 3.1 MTJI-S. M)l. .win. p. L>'.i7. i 



i'. Colony 8 to 10 inches high, consisting of a central geniculate stem, giving 'forth 

 branches which themselves branch in a tlabellate manner; stem not fascicled, annulated above the 

 origins of the branches. Pedicels borne on rather short processes or shoulders of the branches, 

 distinctly annulated, short. Hydrotheca 1 triangular in outline, margin entire. 



(;niKHime. Gonangia borne in axils of pedicels, oblong ovate, with a terminal collar and large 

 round aperture. Medusa' not described, so far as I can ascertain. 



Dixtribatiriii. Found in rocky tide pools (Hincks). Off Thimble Island, 4 to 5 fathoms. Woods 

 Hole, in the passage (Yen-ill). 



Obelia cornmissuralis McCr. Fig. :!i>. 

 I I'rocw.linirs Klliolt Sor.. vol. i. No. 1, p. 197.) 



Ti'H/'liox'iiiK'. Colony attaining a height of <> to 8 inches, consisting of a central geniculate stem 

 giving off branches as in <>. t/iilu'l/n/n. Pedicels not borne on distinct shoulders of the branches, 

 distinctly annulated. 1 tydrotlicr.-i' cumpamilatc. often snbtriangular, but considerably deeper than 

 in <>. tloliflMii. 



37. Obelia ilirholoma (Linn.). 



3X. Obeliaffeniculata (Linn.). 

 A. Medusa. 



39. Obelia gekttiuota (Pallas). 



A. Portion of fascicled stem (enlarged), 



(iviiofome. Gonangia much as in the last species, but larger and less distinctly ovoid. Medusae 

 at literation with 1(1 marginal tentacles. 



Distribution. Growing profusely on docks and floating timbers. Abundant all along the New 

 England coast. 



The branching is exceedingly elegant and delicate, forming feathery verticillate tracery around 

 the slender central stem. 



Obelia dichotoma (Linn.). Fig. 37. 

 (Scrtularia rlichotoma Linn., Syst. Nat., p. 1312.) 



Ti-ophosome. Colony branching irregularly, the branches tending to assume an erect posture, 

 not subverticillate. Pedicels short, usually with 4 to 6 annulations, but sometimes with many. 

 Hydrotheoe large, deeply campanulate, with straight sides and no teeth. 



Gonosome. Gonangia long, slender, widening toward distal end, and terminating in a beveled 

 collar. Medusae at liberation with 16 marginal tentacles. 



Distribution. Rather shallow water. Off Gay Head, 8 to 10 fathoms. (Verrill.) 



I suspect that this is the same species as Eucope pyriformis A. Ag., but, not having seen his types, 

 I can not be certain. 



