44 



BULLETIN (>F THE BUREAU OF FISHERIES. 



Ontogeny imperfectly known. Ova develop within Hit- genital folds, the larvae being later dis- 

 charged a* actinuho. 



Colors. — Bell transparent, with bluish milky tint, genital folds and oral ridges of similar tints. 



Distribution. — Very common at times at Woods Hole and in adjacent waters. Agassiz reports the 

 species extremely abundant at Xabant, Boston Harbor, and Massachusetts Bay during early spring, 

 May and June. Its occurrence seems to be somewhat erratic, however, as [ have taken specimens 

 but twice within recent Years. 



MELICERTTJM" A. Agassiz I 1862). 



Melicertuni campanula A. Agassiz. 



Melicrrtum campanula A. Agasvi/, in L. Agassiz, Contributions to Natural History United States, Vol. TV, 18fi2, p. 349; 

 North American Acalephse, 1865, p. 130. Haeekel, System der Medusen, 1879, pp. 136-7. 



Me'dusa bell-shaped, aboutashigh as broad, capable of consider- 

 able change of form by erratic contractions of the umbrella. Marginal 

 tentacles numerous in the adult, hut the young resemble Laodicea in 

 having but 2, later acquiring others. Radial canals s in the adult, 

 only 4 in early life. Manubrium much as in Laodicea, oral lobes 8, 

 with sinuous edges. 



Ontogeny. — Medusa derived directly from the hydroid stock. Its 

 development has been followed by A. Agassiz i op. cit., p. 134). 



' '"/"/-. — Bell light oeher; gonads and bases of tentacles brownish. 



Distribution. — Massachusetts anil northward (L. and A. Agassiz). 

 So far as I am aware, the medusa has not been recorded at Woods 

 llole, though likely to be found at any time. 



ORCHISTOMA Haeekel ( 1879). 

 Orchistoma tentaculata Mayer. Text cut. 



Orchistoma (tfntaettto/a Mayer, Bulletin Museum Comparative Zoology, Vol. XXXVII. 



1900, p. 8. 



Mayer describes an immature specimen taken at Newport which 

 has the following specitic characters: Bell slightly flaring near the 

 margin, gelatinous substance of upper portion very thick; marginal 

 tentacles 32, in various stages of development, the longest about one 

 and one-half times the height of bell and with hollow basal bulbs; 

 radial canals, lti functional ones, and 16 others in process of develop- 

 ment; velum well developed: manubrium flat and shallow, with 8 lips; 



gonads undeveloped. 



Colors. — Bell transparent, basal bulbs of tentacles a delicate green. 



A medusa taken at Woods Hole, resembling this in many respects, I have considered as probably 

 the young of Rhegmatodes. 



•'This generic term uus apparently first employed by Oken in 1816 i Lehrb. der Naturgeschichte), and Die eery similar 

 term M elicerta was proposed by Peron & Lesueur in 1*09 in designating a Greenland medusa, presumably identical with 

 that later described by Oken. In 1X'«> Eschseholtz, under the binomial here used, described with somewhat mere detail 

 and accuracy a medusa quite similar. Fabricius, however (Fauna Grcenlandica-, 17sn, p, 366), bad used the same specitic 

 term in describing probably the same, or a similar medusa. 



Haeekel has shown (System der Medusen, p. 139), that all these earlier accounts were either so inadequate or inaccurate 

 as to leave serious doubt whether the medusa described by A. Agassiz (op. cit.) with critical detail was identical with 

 that of the earlier accounts. He therefore proposes to credit both the generic and specific terms to the latter, and so 

 designates them in his account (op. cit.). While in strict conformity with established usage the priority of the oldc 

 descriptions should have recognition. I have accepted Haeekel' s version and leave a final adjustment for those having 

 larger concern in problems of synonymy. 



Orchistoma tentaculata. 

 Mayer 



