ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 765 



becomes inclosed by the follicular epithelium ; this may be called 

 the follicular ovum. It must not, as it ordinarily is, be regarded as 

 equivalent to the primordial ovum, but as forming a part only of it ; 

 it is the primordial ovum after the loss of the daughter-cells. 



The history of the ovarian nucleus is next entered on ; from his 

 observations the author is led to conclude that the protoplasmic body 

 of the ovarian cell constantly grows in a centrifugal direction at the 

 cost of the nucleus ; in Colymbetes this is at first quite regular, for 

 continuous superficial layers of the nucleus are added to the proto- 

 plasmic body in the form of rings ; later on, this process of growth 

 is localized in certain parts of the periphery of the nucleus, and in 

 this way bays and buds appear on its surface. As the process goes 

 on these become more and more irregular. Towards the end of egg- 

 formation this growth gradually ceases. Looked at morphologically, 

 these phenomena teach us that there is no " dualism " in the cell ; 

 there is no real distinction between nucleus and cell-body ; the conclu- 

 sion to which we are led is that there was a stage in which the whole 

 cell was still nucleus. 



The history of the protoplasmic body forms the subject of the 

 last division of this essay. It is at first quite clear and achromatic, 

 and appears to be exactly similar to the substance of the nucleus ; 

 with increasing age it becomes chromatic ; later on it becomes 

 spotted owing to the formation of vitelline elements, which are all 

 formed in and by the egg itself. The giant and smaller epithelial 

 cells appear to be the homologues of the cells which, in the male, do 

 not atrophy, but form the spermatozoa. In the female they have no 

 function, but are only of historical interest, indicating, as they seem 

 to do, the primitive hermaphroditism of the primordial ovum. 



Embryology of Armadillos.* — It is a belief among the people of 

 South America that armadillos bring forth only male young. Dr. H. v. 

 Ihering communicates the results of some important observations he 

 has made on this and other points in the history of development of 

 the armadillo, Praopus hybridus. He states that all the foetuses 

 taken from two females presented the external characters of males 

 only. He also states that several foetuses — six or more — are inclosed 

 in a single chorion, which is surrounded by as many zonary placental 

 as there are foetuses, the placentae not, however, forming perfect zones. 

 He finds that the ungual phalanges at this period differ entirely from 

 that of the adult. Instead of being long and claw-shaped, they are 

 wide and hoof-shaped, with a trilobate margin, as in the extinct genus 

 Gyptodon. This is highly interesting, as exhibiting the law of 

 acceleration modifying that of heredity. The sexual characters are 

 probably like those of the hyaenas, in that the female foetus has a 

 clitoris so large as to give her a close resemblance to the male. 



Post-embryonic Development of Vitelline Sac of Birds.f — MM. 

 Charbonnel-Salle and Pbisalix had their attention directed to the 



* Araer. Natural., xx. (1SSG) pp. 667-S. (Reported by Mr. E. D. Cope from 

 * Kosmos.') 



t Comptes Renclus, cii. (18S6) pp. 149(5-8. 



