SUMMARY OF CURRENT RESEARCHES 



RELATING TO 



ZOOLOGY AND BOTANY 



(principally inveetbbrata and cryptogamia), 



MICROSCOPY, Etc.* 



ZOOLOGY. 



VERTEBRATA. 

 «• Embryology. + 



Oogenesis in Mammals.} — A. Louise Mcllroy has studied the de- 

 velopment of the germ-cells in the mammalian ovary, with special 

 reference to the early phases of maturation. Her material was based on 

 human embryos, puppies, kittens, aud rabbits. The same plan of de- 

 velopment is followed in the varied types, but differences arise in the 

 rate of development ante- and post-natal, the cells maturing from the 

 periphery inwards. 



The capsular epithelium is derived from the oogonia, and is differenti- 

 ated at a very early stage. It has only a protective function. 



Mitosis occurs among the oogonia, and also among the primary 

 oocytes of the reticular stage. It ceases at a given stage in the develop- 

 ment of the ovary. 



Large cells — giant or resting cells — occur in the reticular stage of 

 the primary oocyte. " Pfliiger's tubules " are columns or clusters of cells 

 derived from the oogonia, separated off by means of the stroma cells. 

 The growth of the stroma and germ-cells is mutually correlated through- 

 out the development of the ovary. The follicle cells, which form the 

 cells of the stratum granulosum, are derived from the oogonia. and not 

 from the stroma cells. The latter are only supporting and vascular. 



The reserve cells (oogonia and regressive oocytes scattered through- 

 out the ovarian tissue) may function as follicle or as interstitial cells: 

 tin -y may become absorbed as pabulum for the developing oocyte. The 

 primary oocytes undergo transformations in their early maturation stages, 



* The Society are not intended to be denoted by the editorial " we," and they 

 do not hold themselves responsible for the views of the authors of the papers 

 noted, nor for any claim to novelty or otherwise made by them. The object of 

 this part of the Journal is to present a summary of the papers as actually pub- 

 lished, and to describe and illustrate Instruments, Apparatus, etc., which are 

 either new or have not been previously described in this country. 



t This section includes not only papers relating to Embryology properly so 

 called, but also those dealing with Evolution, Development, Reproduction, and 

 allied subjects. 



% Proc. K. Soc. Edinburgh, xxxi. (1910) pp. 151-78 (6 pis.). 



