422 HYBOCODON PROLIFER. 



Massachusetts Bay. It is a strongly marked genus, while its well-developed medusae, each with 

 its single tentacle and unsymmetrical bell-margin, indicate a decided approach to Conjmorpha. 



Hybocodox proltter, Agassiz. 



Hybocodon PROLIFER, — Agassiz, Contr. Nat. Hist. U. S., vol. iv, p. 24.3, pi. xxiiia, figs. 

 10, 11, and pi. XXV. A. Agassiz, Illustr. Catal. N. A. 

 Acal., p. 193. 



TROPHOSOME.— Hydrocaulus consisting of solitary or sparingly aggregated 

 stems, wliich attain a height of about two inches, the stems gradually enlarging from 

 the base, until just below the hydranth they attain a thickness of one sixteenth of an 

 inch; PERISAEC destitute of annulations, except towards the summit of the stem, 

 where it becomes dilated and furnished with annular constrictions ; ccenosarc with 

 longitudinal orange-red striae. Hydranth with its two distal verticils composed each 

 of about sixteen tentacles, the more distal of the two consisting of tentacles which 

 are about half the length of those forming the other. 



GONOSOME. — Umbrella of medusa with five orange-red granular bands, which 

 extend upon its outer surface from the codonostome to within a short distance of the 

 apex, two of these bands lying one on each side of that radiating canal which 

 corresponds to the solitary tentacle, the others lying one over each of the three 

 remaining radiating canals; bulbous base of the marginal tentacle large and 

 proliferous ; tentacle smooth for some distance from the base, and then to its extremity 

 covered with annular groups of thread-cells. 



Colour. — Deep orange-red. 



Development of gonosome. — January. 



Habitat. — In pools of pm-est sea water at low-water mark. 



Batliymetrical didribution. — Laminarian zone. 



Locality. — Massachusetts Bay, Agassiz. 



Hobocodon jirolifer, the only representative yet discovered of its genus, forms the subject of 

 one of the beautiful plates in Agassiz's ' Contributions to the Natural History of the United 

 States.' One of its most striking features is found in the constant tendency of its medusae to 

 multiply themselves by the formation of buds which are developed from the marginal termina- 

 tion of one of the radiating canals, that, namely, which is continued into the solitary tentacle. 

 The buds are produced in clusters from this point, and when each attains a certain stage of 

 maturity, it gives rise in the same way, and from the corresponding point of its radiating canal 

 to a similar brood of medusa-buds. 



