564 Chas. W. Hargitt 



as had beeu maintaiued l)y Ciamiciax and later confirmed bv Weis- 

 mann. I am iucliued to regard both as true ; or in other words, 

 tliat the germ cells probably arise ratlier indiscriminately in botb 

 positions, though in some specimens rather predomiuantly in the 

 oue region and in others equally pronouneed in the other region. 

 As I have elsewhere shown this to be the case with species of 

 Eudendrium, it is unnecessary to more than mentiou the matter in 

 this connection. It woiild seem that in this S})ecies we have a 

 hydroid in which the differeutiation of the body cells of the two 

 layers is physiologically less sharp than in others. 



The growth of the Qg^ is quite similar in most respects to that 

 of other species of Tubulär ia, such as larynx, as described by 

 DoFLEiN^, and crocea, as described by Allen 2. It has not been 

 possible to confirm Brauer's view that those germ cells which are 

 to give rise to eggs are sharply difterentiated before they come 

 into the gonophore, or during their migration thitherward. On the 

 other band the view of Doflein that their impulse toward active 

 egg development is the result largely of positiou and nutrition in 

 the gonophore seems b}' far the more probable, and is in general 

 agreement with similar facts in the case of other species. 



Of the large number of germ cells which crowd the mature 

 gonophore a comparatively few, perhaps three or four, assume the 

 character of ova at any one period of development. Their growth 

 results from the active absorption of their less fortunate fellows, as 

 has been shown in many other cases, as by Allen and Doflein, 

 previously cited, and by the present writer in the case of Pennaria 

 (op. cit.). 



As in the case of most Tubularians, after the development and 

 liberation of one series of embryos other of the i)rimordial germ 

 cells proceed to grow as the former had done, and thus the process 

 continues for several generations. The case is very differeut, of 

 course, in species with free medusae, like Pennaria. Here the eggs 

 are all discharged at about the same time and the medusa dies 

 shortly after; hence most of the germ cells are cousumed in the 

 growth of the first series of eggs. The same is i)robably true in 

 most short-lived medusae, but with many others, successive gene- 

 rations of eggs are produced during the entire breeding season. 



1 Zeit. Wiss. Z. 62. Bd. 1896 pag. 61. 



2 Biol. Bull. Chicago Vol. 1 1900 pag. 201. 



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