ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 975 



mesodermal ovules) imbedded in the stroma, and particularly abundant 

 at the level of the hilum. 



3. The above hermaphroditism is of but short duration, the cortical 

 or female ovules disappear from the testes by the eighth or ninth 

 day, and the medullary or male ovules have by the tenth day dis- 

 appeared from the ovary. In regard to mammals he affirms, with 

 some peculiarities, the same three stages of germijjarity, hermaphro- 

 ditism, and uni sexuality, alike for ontogeny and phylogeny. 



Formation of Spindles in Mammalian Ova during the Dege- 

 neration of the Graafian Follicle.* — Dr. W. Flemming commences 

 his paper by a short description of the methods employed in hardening 

 the ovaries for histological investigation. It appears that in ova from 

 normal follicles there are never any caryokinetic figures in place of 

 the nucleus, and that, since these latter do occur in the ova of dege- 

 nerating follicles, the few instances where they have been described 

 in normal mammalian ova are probably due to some pathological 

 condition. It seems probable that the ova with caryokinetic fi<nires 

 were in no case living ova, since they were fiattened and abnornial in 

 shape, and the follicle itself was evidently undergoing a process of 

 retrogression. It is by far the most natural hypothesis that the 

 degeneration of the follicular ejiithelium is the primary process and 

 that by reason of this abnormal vital processes were caused in the 

 ova ; the result being a premature and perhaps not typical formation 

 of directive-spindles. 



Significance of Cell-nuclei in the Processes of Heredity.t 



Prof. A. Kolliker reminds the reader that iu his Text-book of Embryo- 

 logy (2ud edition, 1882J he insisted on the fact that the first nucleus 

 of the embryo, arising by the conjugation of a male and female 

 nucleus, is the sole means by which we can explain the processes of 

 inheritance. 



The spermatozoa are first discussed, and it is pointed out that the 

 filament gradually grows out from the nuclei of the cells, that it is not 

 comparable to a cilium, inasmuch as it may be found rolled up within 

 its formative colls ; and in many cases a number of the filaments arise 

 within one cell. 



The author propounds the following questions, and considers the 

 answers to them : What portion of the spermatozoon is the fertilizer ? 

 What share is taken in fertilization by the germinal vesicle and the 

 modes of union of the spermatic and ovarian nuclei ? After d'iscussins 

 the opinions of various authors, the Avriter suggests that the removal 

 of certain constituents of the germinal vesicle diminishes the dis- 

 proportionate size of the female nucleus, so that the idioi^lasm of tho 

 two nuclei is more evenly balanced. 



Kolliker is of opinion that tho processes of heredity are to bo 

 understood solely by a reference to tiio phenomena of reproduction • 

 the fertilizing organisms handover to the fertilized a morphologically 

 definite substunco of typical composition, tho activities of which 



♦ Arch. f. Anat. u. Phys., 1885, pp. 321-4 (2 ph.) 

 t ZeitBchr. f. Wias. Zor.l., xlii. (Is85; pp. l-Kj. 



