HYDROIDS OK THK WOODS HOLK UKGION. 341 



Ti'i.jilioHfiiiii: Stt'ia with distinct, deeply anmilatcd cxjtim<jj<>n just below hydrunth. Hydranth 

 with a proximal whorl n\\i\ J,\yq d;stiu.ct bi\t c.losely approximated distal whorls of filiform tentacles. 



GotUMKimr. (Jonophqrtts attac.hpd ^jwi-tly to the hydranth }yOi(]y without the intervention of 

 peduncles, and developing hitft f^ee meduan, each of which has a singly large tentacle bearing suceeed- 

 ing gei\i3\t ions of H\e.(\U<*- Mt^".""' deeply campanulate, with 4 ratljal canals and a short proboscis. 



Hybocodon prolifer Ag. pig. 7<i. 

 {Com. Xnt. Hisl. T. S.. iv, p. -Jl:l. i 



V')v/y/ijn4.(.,t. . - Ilydroeaulus unbranched, longitudinally striped owluu to thu ixeiiosurcal canals 

 showing tlirough; perisarc suddenly enlarging near the hydranth, where a number of collar-like 

 swollen rings api>ear, the uppermost lieing the largest. Jiytlrailth IWK'h h'ke that of Tnlmlanii, but 

 with two distinctly separated whorls of tentacles around the proboscis, each whorl being composed of 

 about 16 tentacles, the lo,\YPV l>t'-i"g twit* s long a" the upper. 



<IHH<UUHH<: (ionophores adnate to the hydranth body just above the basal whorl of tentacles, 

 producing free medusi' with four radial canals and five superficial meridional orange-colored bands, 

 when fully mature. The single tentacle is greatly enlarged, and near its base a number of medusfc in 

 various stages of development are attached, and these again may in the same manner bear still other 

 groups of inedus.'c. 



Color. The pigmentation of both hydranth anil medusje is orange red. 



Distribution. Deep pools of sea water (Agassiz). The medusa only has teen taken at Woods 

 Hole, being collected in the tow net by Mr. Vina] Kdwards 011 March '2, At that time the or&nge 

 bands were not conspicuous. 



Hydnitheca- and gonangia jir<iseilt. 



Ti-o/i/iiiMiiiti: Hydrothecui wt'H developed, nonojjereulate, either with distinct pedicels or nearly 

 sessile, but not adnate to or partly immersed in stem or branches. Hydrothecal cavity distinctly 

 differentiated from cavity of stem by a septum perforated to allow a co>nosarcal connection between 

 hydranth and pedicel. Hydranth with a tnun])et-shaped or subglobular proboscis. 



(loiioxoiiif. (ionophores either developing the generative products directly or producing medusse 

 which usually have otocysts, and in which the ovaries are situated along the course of the radial 

 canals and sometimes on the prolx>scis also, but never on the proboscis alone. 



Ki'ij tn ijeni'fii nf f'liiit/Hiiinliii'iil.v fiimiil in tlie Wooth Hole region. 



A. Stein iinl n-iiularly Uriiiu'luHl. 



o. Hydrotlu-ca- on IOIIK pedicrls. 



It. Fri-t- nu-'liisit with four imirginal toiitaclL-s nt birth ..... , ................................................. Ctytia. 



1>'. No im-dusji-. Kcprmlnctioii by phinulio ........................................................... CampaHularia. 



n'. Hyirothrcif tubular. Pedivi'ls short. Miirgin o( hydrothocse entirr, not toothtnl .......................... Hebella. 



A'. Stem rcK"larI\- l>ranche*l. 



it. Fr<f ?iH'<tMs;i' \vitli Id or more innrKiual tontacles. Litlmt-ysts on tlu 1 bases of tentacles ..................... Obelia. 



a'. No free mednsf. the mature Konaiimia bearing meilusa-likc sporosncs on their summits ............... Hmmtlujra-ir. 



n". No fro i meilu;e, the planulse being developed within the gonangiura ............................... Campanularia. 



The Onmpanidaridx offer great difficulties in iilentilication, owing to the necessity of basing generic 

 characters on the gonosome and the practical identity of the trophosomes of different genera. The 

 following entirely artificial key, although inadequate in .some cases, is presented to aid the collector 

 and student in the identification of specimens without the gonosome. 



