SUMMARY OF CURRENT RESEARCHES 



RELATING TO 



ZOOLOGY AND BOTANY 



(principally invertebrata and cryptogamia), 



MICEOSCOPY, Etc.* 



ZOOLOGY. 



VERTEBRATA. 

 a. Embryology. + 



Gestation in White Mice.J — J- Frank Daniel notes that the general 

 estimate of the period of gestation in white mice as twenty-one days, 

 requires considerable modification. The period in non-suckling mothers 

 is practically twenty days ; in suckling mothers the period seems to be 

 very variable. Not only does one mother differ from another in period 

 of gestation, but the same mother at different times shows considerable 

 variability. The minimum is twenty-two, the maximum thirty. It 

 seems that the period of gestation, in lactating mothers, varies directly 

 with the number of young suckled. The delay due to lactation may 

 operate by retarding ovulation, but the author thinks that it operates by 

 retarding the development of the young before birth. 



Factors of Traumatic Parthenogenesis.§ — E. Bataillon discusses 

 the occurrence of artificially induced parthenogenetic development in 

 Amphibians. Electrical stimulation may induce more or less pronounced 

 cleavage, but it never goes as far as gastrulation. Puncturing with a 

 thermic cautery leads to cleavage, but in the puncturing something gets 

 in — a leucocyte or some serum — something not specific. Bataillon dis- 

 tinguishes this traumatic parthenogenesis from that induced, for instance, 

 in Loeb's experiments, but we have not been able to get a clear view of 

 his position. 



Alleged Lactation of Male Lepus bairdii.|| — A. Berger discusses 

 E. Hart Merriam's (1872) description of adult males of Lepus bairdii. 



* 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 

 published, 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. t Journ. Exper. Zool., ix. (1911) No. 4, pp. 865-70. 



§ Comptes Rendus, clii. (1911) pp. 920-2. 



I! SB. Ges. Natur. Freunde Berlin (1910) No. 7, pp. 305-6. 



