194 WTLLTA^I WALLACE. 



the trout. It seems that in this species sometimes the whole 

 batch of ripening ova for one spawning- are reabsorbed. 

 Consequent!}', at the breeding season, a certain proportion of 

 the females are unripe; not because they have not reached 

 that age at which sexual maturity is attained, but on account 

 of the retention of the season's ova. For some reason, at 

 present obscure, the dehiscence of the follicles containing' 

 these eggs had not been brought about. These unspawned 

 ova then undergo fatty degeneration. Further, according to 

 Barfurth (1886), the presence in the ovary of these inert 

 degenerate masses may hinder the production of ova for the 

 next spawning period. Accordingly the unripe condition of 

 certain individuals may last for two years or more. To what 

 extent this phenomenon, viz. the reabsorption of an entire 

 crop of ripening ova, is prevalent in Teleosteans is unknown. 

 One specimen of Zoarces was found in this condition at the 

 breeding season on September 18th, 1901. Another is men- 

 tioned by Stuhlmann (1887, p. 33). 



In regard to the histology of egg absorption, Barfurth 

 states that a growth and perhaps a proliferation of folli- 

 cular epithelial cells, and an immigration of these cells into 

 the interior of the egg, accompany the degeneration of the 

 latter. Barfurth considers that leucocytes play only a sub- 

 ordinate part in the process of reabsorption. His figures 

 show what are apparently initial stages. In one figure 

 (fig. 12) the germinal vesicle is absent, and a few round dark 

 bodies, which may be cellular or nuclear, are embedded 

 about the centre of the yolk. In the figure of another egg 

 (fig. 15) the follicular epithelium around the egg is thicker, 

 and contains fat drops. 



Stuhlmann (1887, p. 20) observed that in immature ovaries 

 of Zoarces certain of the follicles contained, in place of an 

 eorg", a ''Zelldetritus," in which degenerate remains both of 

 ovum and granulosa could be made out. The '^ detritus" 

 was surrounded by a ''cuticle," and the whole was contained 

 within the vascular connective-tissue sheath (" innere Gefils- 

 schicht ") or " theca folliculi." At another place (p. 83) in 



