550 Chas. W. Hargitt 



capsule may often be found iu a partially collapsed condition upou 

 tlie stem or branclies. 



Medusa piriform, with prominent apical projection. 8ize 2 mm 

 high by 1.3 mm broad. Velum narrow, velar openiug- verv small. 

 Manubrium rather large, conical and devoid of peduncle. Bell very 

 transparent, with scattered nematoeysts over the exumbrellar surface. 

 Radial canals lacking, marginal canal simply a fissure of varying 

 size between the layers of ectoderm with vestiges of entodermal 

 lining near the margin. Tentacles entirely lacking. The medusa 

 is devoid of color except on the manubrium , which varies from 

 orange to dark brown. Mouth wholly lacking. When first liberated 

 the medusa swims with a short, jerky motion, tho of limited vigor, 

 a few contractious appeariug to exhaust the little creature. Eggs 

 are discharged almost immediately after the birth of the medusa, 

 the life of which is very ephemeral, not exceeding one or two hours 

 (Fig. 2). 



Origin of the Germ Cells 



Concerning the origin of the germ cells my observations upon 

 this species agree iu most points with those of Weismann on the 

 related species, in so far as actual conditions are concerned. He 

 tìnds these cells in the entoderm, and there only, yet rather insists 

 upon the probability of their descent from ectoderm cells, while as 

 yet in an iudistiuguishable stage. His specimens beiug ali male in 

 which, as he says, the primitive germ cells are small and correspon- 

 dingly difficult of recoguition, affords some plausibility for his con- 

 teution, tho he likewise makes similar claims concerning the ulti- 

 mate source of egg cells in other genera. 



These speculative deduetions are without any support from my 

 own ol)servations, tho as already noted, they were restricted to fe- 

 male colonies entirely and therefore cannot of course be claimed to 

 l)rove those of Weismann to bave been wholly in error. In the 

 species under consideration the germ cells originate in the entoderm 

 and are not fouud elsewhere at any time during their growth or 

 maturation. As is very well known, the size and character of the 

 egg cells render them easily distinguishable even at a comparatively 

 early period in their development. In sections of the hydroid stem 

 in both long and cross series and staiued by various methods I 

 bave found no evidence of their occurrence other than in the ento- 

 derm. 



