ZOOLOGY AND BOTANY, MIGEOSCOPY, ETC. 631 



the peduncle which attaches it to this membrane does not divide 

 until it has attained' its definite size ; the corpuscle then commences 

 to traverse the yolk. The first cells which leave the yolk become 

 arranged in a delicate and continuous layer, formed of flattened cells, 

 each provided with a small nucleus ; this is the follicular envelope. 

 The cells of the next set are thicker, and form a layer internal to 

 the first ; this is the papillary layer. Finally, the ovum, the yolk of 

 which is beginning to be charged with granules of lecithin, gives rise 

 to a third endogenous generation ; these, however, are only homo- 

 geneous globules, which have no relation to the germinal vesicle ; 

 they form the testa. Fol regards the follicular cells as being gene- 

 tically the exact homologues of the spermatoblasts or mother-cells of 

 spermatozoa, while the ovule itself corresponds to the polyblast, or 

 male ovule of Duval. 



Cells of the Ovarian Follicle.* — A. Sabatier discusses the views 

 of Fol and of Eoule on the follicular cells ; dealing with those of the 

 former, who believes that the bodies in question are the result of a 

 local budding from the nuclear envelope and the nucleus itself, he 

 states that an attentive microscopic study has always convinced him 

 of the presence of a surface of separation between the so-called bud 

 and the nucleus. The differences between the statements of Fol and 

 Eoule are sufficient to justify a doubt as to the correctness of cither's 

 views as to the function of the nucleus or nucleolus, and Sabatier 

 remains firm to his opinion that the follicular cells arise endogenously 

 in the vitellus. Similar observations may be made on Vertebrates of 

 various groups, and this widely observed elimination of cellular 

 elements is very striking ; they lead, indeed, to certain generaliza- 

 tions as to the nature and origin of the sexuality of the reproductive 

 elements. These are already known to the readers of this Journal,"j" 

 but attention is to be directed to the present communication, as it no 

 doubt affords some of the " further evidence " which the author 

 promised in his essay on spermatogenesis in the Nemertinea. 



Bizzozero's New Blood-corpuscle and Norris's Third Corpuscular 



Elenient.+ — G. Hayem insists that the elements of the blood to which 

 he gave the name of hematoblasts are identical with the objects which 

 have since been described by G. Bizzozero § as " plaquettes." Norris's 

 third corpuscular element || he considers to be a red corpuscle 

 decolorized as the result of the manipulation to which the blood is 

 subjected. 



Colour-Markings of Mammals.lF — Professor Eimer has continued 

 his studies in regard to the colour-markings of vertebrates. 



As the result of his observations, he has laid down certain general 



* Comptes Eendus, xcvi. (1883) p. 1804-6. 

 + Ante, pp. 212-3. 



X Comptes Eendus, xcvii. (1883) pp. 458-61. 

 § See this Journal, ii. (1882) p. 480. 

 II Ibid., iii. (1880) p. 229. 



^ Jahresb. Verein Vaterl. Naturk. Wiirtt., xxxix. (1883) p. 56. Science, ii. 

 (1883) pp. 144-5. 



