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PROCEEDINGS OF THE 



[April, 1857 



tended with large embryos, has an almost ovoid form, which is 

 exchanged for the cylindrical one described, after their expulsion. 



I found the hydroid of this Medusa as late as November 24th 

 as well as during the summer months, but have not hitherto suc- 

 ceeded in procuring specimens of it during the winter. It may 

 be, however, that only those polypidomata growing near the sur- 

 face are killed by the cold, and consequently it may exist during 

 winter at some distance below the surface. 



Remark. — The identity of Eucoryne elegans (Leidy) with Globi- 

 ceps tiarella (Ayres) is acknowledged, and was in fact pointed out 

 to me by Prof. Leidy himself. The generic identity of Globiceps 

 with the Sertularia pennaria of Cavolini may be seen at a glance 

 by comparing this description and Leidy' s figure and description 

 (loc. cit.) with those of S. pennaria by Cavolini. (Polyp. Marin, 

 p. 134, pi. 5, fF. 1-6.) 



ii. tubularid^e.* Johnston. 



General form spherical, conical or cylindrical. Tentacula 

 sometimes four, sometimes one only, sometimes altogether want- 

 ing. Ocellus wanting. Digestive trunk cylindrical or flask- 

 shaped, and probably in general it will be found elongate. Sexual 

 organs apparently equally distributed around the walls of the 

 digestive trunk. Mouth simple. But the character which, if 

 constant, constitutes the greatest peculiarity of the group, is a 

 series of longitudinal crests which inEuphysa, Steenstruppia, and 

 certain attached species of Tubularia, ornament the bell-margin, 

 springing from the line of junction of the bell-wail and vail and 

 rising upward along the exterior of the disk for a short distance. 

 These crests are distinct from the tentacula, existing frequently 

 without them, and the tentacula when present are attached to their 

 lower extremities. They are also distinct from the marginal 

 bulbs, since they are out-standing processes of the exterior of the 

 bell. They seem to be simple epidermal protuberances containing 

 irregularly arranged thread-cells. 



The larvae of these Medusas differ from Pennaridee, by having 

 both whorls of tentacula simple and inclavate. The lower basal 



* It will be seen by reference to the scheme, p. 123 of this paper, that I include 

 among Tubularidae proper, Forbes' two genera Steenstruppia and Euphysa. To 

 this I was led by a fact communicated to me some years ago by Prof. Agassiz, 

 that he had observed the liberation of a species of Steenstruppia from a Tubularia 

 of the coast of Massachusetts. 



