SUMMARY OF CUREENT RESEARCHES 



RELATING TO 



ZOOLOGY AND BOTANY 



(principally invertebrata and cryptogamia)^ 



MICROSCOPY, Etc.* 



ZOOLOGY. 

 VERTEBRATA. 



a. Embryology, f 



Reproductive Cycle in Dasyurus viverrinus.| — J. P. Hill and 

 Chas. H. O'Donoghue find that this Marsupial is monoestrous, with 

 one breeding season in the year in the winter months (end of May to 

 first fortnight in August). The male does not appear to experience a 

 marked rutting season ; copulation is as described by Selenka in Didel- 

 phys. The sperms can remain alive in the Fallopian tubes for at least 

 two weeks. 



The ancestral period lasts more than half the year. The prooestrus 

 appears to extend over a varying period of from four to twelve days. 

 During this time the lips of the cloaca become swollen, the pouch en- 

 larges somewhat, and becomes shghtly tumid and moist, the Graafian 

 follicles increase in size and become vesicular ; the uterine mucosa 

 increases in thickness and becomes more vascular, its glands lengthen 

 and become convoluted, and the uterine epithelium also tends to thicken. 



CEstrus lasts usually for one or two days, and is the period during 

 which copulation occurs. The changes already initiated during prooestrus 

 in the various parts of tlie reproductive system are continued without 

 interruption. The prooestrus, or period following oestrus and terminated 

 by ovulation, occupies, as a rule, about five or six days. The tumidity 

 of the cloacal lips disappears, but the changes in the pouch and uterus 

 still continue, not, however, very actively. In the ovary the ova give 

 off the first polar body, and the spindle for the second meiotic division 

 is formed. The follicles attain maturity and ultimately rupture, setting 

 free the ova. 



* 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 puh- 

 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 subiects, 



+ Quart. Journ. Micr. Sci, lix. (1913) pp. 133-74 (3 pis.). 



