ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 283 



2. The daughter-chromosomes (i) undergo towards the end of the 

 metaphase, or during the anaphase, a longitudinal division. 



3. The daughter-chromosomes (i), thus constituted, preserve their 

 autonomy during the interkinesis. They become the chromosomes (u), 

 and the longitudinal anaphasic halves become the constitutive branches 

 of chromosomes (n). 



4. These branches, and consequently the longitudinal anaphasic 

 halves, separate in each chromosome in the second figure. 



Spermatogenesis in Batrachoseps attenuatus.* — F. A. Janssens 

 communicates a third study on the spermatogenesis of this Batrachian. 

 He deals especially with the history of the auxocytes. It is extremely 

 probable that the 12 chromosome-branches (anses de bouquet) result 

 from the fusion in pairs of the 24 chromosomes of the last somatic 

 kinesis, and that the double chromosomes of the prophases of the 

 heterotypic division result from the longitudinal cleavage of the anses de 

 bouquet. 



Testicular Secretion.f — P. Bouin and P. Ancel relate some experi- 

 ments on guinea-pigs which go to show that the results of castration 

 (on the development of the skeleton and accessory genital organs) 

 may be attenuated by sub-cutaneous injections of extract of the inter- 

 stitial gland of the testis. The material for injection was obtained 

 from several large mammals. 



Alleged Ovulase of Spermatozoa .% — Antoine Pizon discusses Pieri's 

 theory of a soluble ferment (ovulase) contained in spermatozoa and pro- 

 vocative of segmentation. His experiments do not in the least confirm 

 Pieri's view : there is no evidence of any such ferment. 



Toxic Properties of Seminal Fluid.§ — G. Loisel has studied ex- 

 perimentally the toxic properties of seminal fluid from many animals. 

 There is, he thinks, no doubt that the testes secrete or excrete toxic 

 substances especially affecting the nervous system. It may be that some 

 toxalbumin carried by the spermatozoa acts as an excitant to the pro- 

 toplasm of the egg. 



Placentation in Ungulates. || — R. Assheton points out that the for- 

 mation of the placenta in Ungulata vera is founded on a system of 

 foldings of the subzonal membrane (or of the trophoblast only), which 

 fit into corresponding grooves in the walls of the uterus, without 

 thickening of the trophoblast layer of the blastocyst, and with- 

 out destruction of maternal epithelium or other tissue (Sus). Certain 

 parts of the crests of the ridges are produced by local amplification into 

 true villi, into which the splanchnopleure of the allantois subsequently 

 extends (Equus, Bos, etc.). This plicate placenta (Ungulates, and 

 perhaps Cetacea, Sirenia, Proboscidea) is contrasted with the cumulate 

 type (in Rodents, Insectivora, Hyracoidea, Primates, Chiroptera), in 

 which the placenta is formed by the heaping-up or thickening of the 



* La Cellule, xxii. (1905) pp. 379-425 (7 pis.). 



t Comptes Rendus, cxlii. (1906) pp. 232-4. 



t Op. cit., cxli. (1905) pp. 908-10. § Tom. cit., pp. 910-12. 



|| Proc. Roy. Soc, lxxvi. No. B 511 (1905) pp. 393-4. 



