§ 8 FREQUENCY IN DIFFERENT GROUPS 113 



adnexa up to a certain level of development (ovipositor in 

 Rhodeus; shell-gland in Amphibia and Selachii), so that, 

 after the completion of ovulation, all that remains for the 

 calyx is to close up the ovulation porus. A different sign- 

 ificance is alotted to the ruptured follicle in all viviparous 

 fishes, v^here the further care of the ovum is of importance. 

 In this case the calyx does not involute, but rearranges itself, 

 through strong vascularisation, for a nutritive function, and 

 does not serve in closing up the v^ound until after the birth 

 of the foetus. Since pregnancy, in these viviparous fishes, 

 takes place in the ovary, the changes necessary to it extend 

 over the entire organ. Strong hypertrophy and extensive 

 vascularisation are characteristics of the pregnant ovary. 

 Here, again, numerous pre-ovulation corpora lutea appear in 

 the pro-estrus and during pregnancy. Their importance 

 probably lies in the production of hypertrophy, hyperaemia 

 and vascularisation of the ovary, and in the calyx nutricius 

 (Fig. 76D). Owing to the long persistance of these calyces 

 nutricii (in Zoarces up to 4 months), the granulosa is, in 

 many cases, luteinised. In this way the calyx nutricius mixtus 

 in Zoarces is formed, which, by its granulosa-luteinisation, 

 shows a similarity to the post-ovulation corpus luteum, and 

 is, therefore, of theoretical significance in the corpus luteum 

 problem. 



§ 8. THE FREQUENCY OF THE FOLLICULAR DERIVATIVES IN 

 THE DIFFERENT GROUPS OF VERTEBRATES 



In order to obtain an insight into the manner in which the 

 numerous follicular derivatives here described are distributed 

 over the various groups of vertebrates, we have examined 

 more closely representatives from all the groups. In Table III 

 these data have been summarized, together with some 

 additional facts from the literature. We see that, in Anamnia, 

 the pre-ovulation corpus luteum is associated with the sexual- 

 endocrine organization, and that the ovulated follicle, as 

 calyx simplex, is represented only by a scar. An exception 

 to this — as we stated before — is formed by viviparous 



