126 



ging from the hydranth (Halocharis Ag.) Medusa, when fully deve- 

 loped, having a deep iimbrella; maiiubrium massive and destitute 

 of oral tentacles; marginal tenlacles four, each with a clavate ex- 

 treraity and with an ocellus on the bulbous base; roof of umbrella- 

 cavity rising in four overarched Spaces between the roots of the ra- 

 diatiug eanals. 



C. Agassizii M'Cr. 



Gymuocoryne Hincks. Hydrocaulus undeveloped. Hydrorhiza a 

 filiform stolon invested with a chitinous perisarc. Hydranths seasile 

 on the hydrorhiza, with numerous tentacles; the distal tentacles 

 disposed in a verticil round a conical hypostome, the others scatte- 

 red over the body. Gonosome not known. 



G. coronata Hincks. 



Gemmaria M'Cr. Hydrocaulus developed, invested by a peri- 

 sarc and rooted by a creeping filiform hydrorhiza. Hydranths clavi- 

 form with scattered capitate tentacles. Planoblasts from the body 

 of the hydranth. Umbrella at time of liberation deep bell-shaped; 

 mauubrium moderately developed, destitute of oral tentacles or lobes ; 

 marginal tentacles two, developed from the distal extremities of two 

 opposite radiating eanals, the alteruate eanals having each e small 

 tentacular tubercle at the corresponding point; the tentacles cora- 

 mence each with a large bulbous dilatation destitute of distiuct 

 ocellus, and are for the remainder of their course set with peduncu- 

 lated sacs fiUed with thread-cells; from the base of each tentacle 

 and intermediate tubercle a coecal claviform tube, filled with thread- 

 cells, extends for some distauce in the walls of the umbrella, parallel 

 to the corresponding radiating canal (Zanclea M'Cr.). 



Gemmaria implexa M'Cr. (= Coryne briaraeus AUm.) 

 ' Fam. Dicorynidae. Hydrocaulus developed, invested by a 

 perisarc. ilydranths with verticillate filiform tentacles. Gonophores 

 in the form of natatory ciliated sporosacs with two simple ciliated 

 basal tentacles. 



Dicoryne AUm. Hydrocaulus consisting of branched or simple 

 stems, which arise at intervals from a creeping filiform hydro- 

 rhiza. Hydranths fusiform with a single circlet of filiform ten- 

 tacles surrounding the base of a conical hypostome. Sporosacs 

 developed upon blastostyles, detaching themselves as natatory pla- 

 noblasts, ciliated over their entire surface and having two filiform 

 tentacles diverging from the proximal eud. 



Dicoryne conferta Alder. (:= D. stricta Allm.) 



Fam. Bimeridae. Hydrocaulus developed and invested with 

 a perisarc, or rudimeutal. Hydranths with the hypostome not 

 abruptly differenciated ; tentacles filiform in a verticil round the 

 base of the hypostome. Gonophores in the form of fixed sporosacs. 



