HYHK01U- Of THh. WOODS HOLK REGION. 369 



HYUROII) MEDUSA FOUND IN THE WOODS HOLE REGION. 



A monographic account of the medusa? is in course of preparation by an eminent 

 authority, and the present writer therefore does not desire to discuss the medusae in 

 a systematic way, but hopes that the key herewith presented will be of service in 

 identifying the medusre known to occur in the region. No attempt has been made 

 to describe new species or to define families, genera, or other groups. The classifi- 

 cation conforms, so far as possible, to the plan of the preceding part of this work 

 when the hydroid form is known. Otherwise the names are the same as those found 

 in Alexander Agassiz's work, North American Acalepha?. Almost all of the illustra- 

 tions are from specimens taken at Woods Hole and Newport, and sketched by the 

 author. 



Ki'ii far tin i'li'ntitirittion nf tin' Hi/ilfoiil meilnmr foil ml in tin' Woods Hole region. 



A. Ovaries attached to the proboscis walls mid never fnmid along the radial canals. Otocysts never present. 

 a. Radial canals I', unbranchcd. 

 b. A single conspicuous marginal tentacle, others, if present, much smaller. * 



r. Proboscis not more than one-half length of bell cavity Euphysa rirffulata, ^ 



c'. Prol.M>seis more than one-half length of bell cavity. 



(I. A single greatly enlarged tentacle from which secondary medusae arise Hybncodon pmlifer. 



/I'. One large and 3 much smaller tentacles. Xo secondary mednsre Corymorpha pendtda. 



b'. Two conspicuous marginal tentacles. Others, if present, much smaller. 

 c. Bell with a distinct .-ij'ie.-il projection. 



tt. Apical projection a lengthened cone Stomatocha apicata. ^ 



il'. Apical projection dome-shaped. Tentacles bearing stalked iienmtoeyst batteries.. Kenimaria cladnphora- V 

 c'. Bell evenly rounded, without apicul projection. 



(I. Tentacles bearing stalked batteries of nematoeysts Corynitis Offassizii- 



d'. Tentacles IK irmal Pcrigonimusjoneri. 



b". Four tentacles of approximately equal length. 



r'. l'rol>oscis and tentacles very long and slender. 



il. Bell outline subspherical Conine m/rabiUs. 



rl f . Bell outline subeonical , Dipurena arnica. V 



r'. Proboscis short, not reaching bell opening. 



(I. Tentacles tightly coiled. Bell with s meridional lines of liwso cells Ertnplcumochracea^ 



d'. Tentacles rudimentary. Xo lines of lasso cells Peiniaria tiarctta. 



il". Tentacles functional. Harlial canals very broad ITydricMhys mirui. 



ft" w . Kight tentacles of approximately equal length. 



r. Tentacles strong, functional. Proboscis bearing secondary medusre Di/smorplmm fitli/umns. ** 



' '. Tentacles rudimentary. Xo secondary. medusa 1 titylactis hoopcri. 



b" ff '. TwUacles more than s. of approximately equal size when full grown, and disposed at regular intervals. 



c. \ large globular or snbconical process on apex of bell Turns rrticarta. * 



r'. Bell evenly rounded above Turriiopsis nutricnla. < 



yrrtr 'i\.ntacles in groups or bunches. 

 <. Kour clusters of tentacles. 



'/. Proboscis small and slender. 



e. A pair of erect elavate tentacles in each group J Xnnoitritbacliel. Y 



/'. Tentacles much alike Bougainrillia mrolinwtis, 



rl'. I'roboscis large and broad BougainviUia superciliarte, 



i". Kight clusters of marginal tentacles Liszia ip-ata, Y 



a'. Radial canals I, branched at their distal ends Willia ornata. v 



a". Radial canals many, bell cup-shaped Orchinioina tentaevlala. 



A'. Ovaries attached to the radial canals, often also to the proboscis. Otocysts usually present, 

 o. Radial canals 4. 



b. Marginal tentacles 4. sometimes with lateral cirri. 



i . Proboscis KSts; long, reaching far beyond the velum. .. 



'I A swelling af base of each tentacle Eutima mim,-!* 



d'. No swelling at bases of tentacles Eutima limpiia. y 



c'. Proboscis short. Bell deep. 

 <l. Tentacles with lateral cirri. 



e. Club-shaped appendages U'tween bases of tentacles , Hebella rtilearata (juv.). 



r'. Xo club-shaped appendages. * 



/. Two ot< K-ysts bet ween bases of adjacent tentacles Euclictlota rCT(riCTi?ri < *- 1 -'* 



/'. Three otocysts between bases ,f adjacent tentacles Eucheilota duodectmalit. "^ 



it'. Tentacles without lateral cirri Clytia bicopkvra (juv,), 



Clylia noliformii (juv.). 

 ' . B. 1899 24 



