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SUiMMAEY 



OF CURRENT RESEARCHES RELATING TO 



ZOOLOGY AND BOTANY 



(principally Invertehrafa and Cryptogamia), 



MICROSCOPY, &c., 



INCLUDING ORIGINAL COJmUNICATIONS FROM FELLOWS AND OTHERS." 



ZOOLOGY. 



A. GENERAL, including Embryology and Histology 

 of the Vertebrata. 



Polar Globules and other Elements eliminated from the 

 Ovum.f — In this important contribution to the theory of sexuality, 

 A. Sabatier sums up our knowledge as to the phenomena of sperma- 

 togenesis : — 



A cellular element belonging to the so-called male gland (and not 

 specially an epithelial cell) grows and acquires a thicker zone of 

 protoplasm ; this first differentiation gives rise to the primitive re- 

 productive cell ; this cell multiplies by division of the nucleus and 

 of the protoplasm ; the resulting agglomeration or group of cells is 

 that which forms the male tubes of Pfliiger, or the poly blasts. The 

 first generation of cells (protospermoblasts) becomes more or less 

 independent, and gives rise to one or more generations of protospermo- 

 blasts. 



Later on, each cellular element, which is definitively male, 

 acquires a thicker " atmosphere of protoplasm," while in the zone 

 which is in direct contact with the nucleus there arise, by concentra- 

 tion and differentiation, that is to say by true genesis, homogeneous 

 hyaline corpuscles, which undergo a further differentiation, and 

 may multiply by simple division. These corpuscles, once formed, 

 take a centrifugal direction, pass to the periphery of the cell, and 

 become converted into spermatozoa. In this way is formed the 

 deutopolyblast, at the surface of which the deutospermoblasts are 

 eliminated. 



• The Society are not to be considered responsible for the views of the 

 authors of the papers referred to, nor for the manner in which those views 

 may be expressed, the main object of this piirt of the Journal being to present a 

 summary of the papers as actunllij published, so as to provide the Fellows with 

 a guide to the additions made from time to time to the Library. Objections and 

 corrections hhould therefor*-, for the most part, be addressed to the authors. 

 (The Rociety are not intended to be denoted by the editorial " we.") 



t Rev. Sci. Nat., iii. (1884) pp. 362-4G2. 



