124 University of California Publications. [zoology. 



interesting' similarity between the origin of the ova in that species 

 and in Crista. Thus, in the young tips, he finds large cells 

 which he considers to be "elements ovulaires." Furthermore, he 

 finds these cells in a cavity of a branch, distal to the region 

 where the polypide buds are found. He says: "Dansles blas- 

 tozoiides jeunes, soit par l'observation directe sur le vivant, soit 

 par I'examen eomparatif des coupes histologiques, on peut suivre 

 pas a pas la genese des differentes parties constitutives de l'ovaire 

 adulte. II n'est pas rare de rencontrer, parmi les elements libres 

 de la cavite d'uu blastozo'ide terminal reuf'ermant un polypide 

 a l'etat de rudiment massif, un certain nombre de cellules qui, 

 par leurs grandes dimensions et leurs caracteres histologiques, se 

 desiguent deja comme elements ovulaires (PI. V, fig. 7et9, ovu) ." 

 His description of these cells leaves no doubt that they are eggs, 

 and his figures show the close resemblance between them and 

 the ova found at the growing points of a colony of Crisia 

 (PI. XII, Figs. 13, 14, and 15). This writer regards the ova 

 which he finds at the growing points of Bugula as exceptional, 

 and not as showing the ordinary method of their development. 

 When so found they constitute merely the "anlage" of the future 

 ovary, and in no case does he find the mature ovary outside of 

 a zocecium containing a polypide. In this respect then. Bugula 

 differs materially from Crista, since in the latter genus the ova 

 which appear among the free elements of the tips of the branches, 

 constitute the ovaries, and it is here that the ovum matures, is 

 fertilized, and unites with a young bud to form an ovicell. 



There is much in confirmation of these observations on the 

 early development of the genital products, and of their inde- 

 pendence in their earliest stages, to be obtained from Harmer's 

 investigations. That writer reports the finding of egg-like cells 

 in the growing tips of Crisia, and says, "The fact that these 

 eggs are commonly found in the growing poiuts, leads me to 

 suppose that several are produced in each fertile internode; 

 apparently by a modification of the funicular tissue, and that 

 their further development depends upon their entering into defi- 

 nite relation with a polypide bud." In Tubulipora ( '98 ) . he finds 

 that eggs are abundant in the young lobes. He found them in 

 many of the zocecia in connection with polypides and polypide 



