ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 621 



lowing an epidemic of conjugation. Another, in a hay infusion medium, 

 died out at the 572nd generation. A third, started from the second at 

 the 360th generation, died out at the 507th generation, following an 

 epidemic of conjugation. 



In the culture kept on the hay medium, conjugation never occurred, 

 and abnormal or degenerating individuals did not appear. But after a 

 gradual decline in the fission rate the culture finally died out. It is 

 believed that this was due not to the ending of any definite life-cycle, 

 but rather to the failure of the hay medium to furnish an environment 

 which was exactly suitable for the continued existence of this species. 



In both of the cultures kept on the beef medium an epidemic of 

 infertile conjugation occurred, and within three weeks after its appear- 

 ance all the non-conjugants in both of the cultures died. The animals 

 were normal at the time of conjugation, but shortly after its appearance 

 degenerative changes were evident. All ex-conjugants passed through 

 degenerative stages, which ended in their death within forty-eight hours 

 after separation without division. The micronuclei were present in non- 

 conjugants, conjugants, and ex-conjugants at all stages. There is no 

 evidence to show that the infertility was due to any abnormal conditions 

 previous to, or during conjugation. The experiments show conclusively, 

 the author believes, that conjugation is induced by external conditions, 

 and that it bears no relation, in this form at least, to a particular period 

 of a " life-cycle." It is suggested that the infertility of the syzygies in 

 these cultures was the result of the fact that the gametes had an identical 

 environmental history. 



Schizogony of Trypanosoma evansi.*— E. L. Walker finds that in 

 the developmental cycle of Trypanosoma evansi, a schizogony takes place 

 in the spleen of the vertebrate host (guinea-pig). The observations of 

 Salvin-Moore and Breinl, Fantham, and Buchanan, that forms similar 

 to the young schizonts of T. evansi occur in the internal organs of 

 animals infected with T. gambiense, T. rhodesiense, and T. hrucei, make 

 it probable that schizogony is a reproductive process common to the 

 Trypanosomata. 



Antelopes as Reservoirs for Trypanosoma gambiense.f — H. L. 

 Duke finds that the reedbuck and other antelopes may remain capable 

 of infecting Glossina palpal is with Trypanosoma gambiense for a period 

 of at least twenty-two months after their original infection with this 

 Trypanosome. There is some evidence to show that an antelope which 

 has ceased to be infective for T. gambiense acquires some degree of 

 immunity against re-infection. 



Studies on Leptomonads.J — E. Chatton describes the life-history of 

 Leptomonas legerorum sp. n. from larvge and adults of Spheerocera sub- 

 sultans L., a small coprophagous Muscid. Another species occurs in 

 the adult of another insect of the same family — miwaXj ,Limosina hirtula 

 Rond. var. thalhammeri Strobl. 



* Philippine Journ. Sci., vii. (1912) pp. 53-62 (1 pi.), 

 t Proc. Roy. Soc, Series B, Ixxxv. (1912) pp. 299-311. 

 X C.R. Soc. Biol. Paris, Ixxiii. (1912) pp. 286-9 (14 figs.). 



