( 844 ) 

 PtECOED 



OF CURRENT RESEARCHES RELATING TO 



INVEETEBEATA, CEYPTOGAMIA, MICEOSCOPY, &c. 

 including Embryology and Histology generally. 



ZOOLOGY. 



A. GENERAL, including Embryology and Histology 

 of the Vertebrata. 



Gestation of the Armadillo.* — Mx-. Milne-Edwards refers to the 

 presence f>f four foetal (nine-banded) armadilloes in a common 

 chorion ; the phenomenon may, he thinks, be explained either (Ij by 

 a number of ovules having been enclosed in the Graafian follicle, 

 inasmuch as these ovules might also be enclosed in a common 

 granular layer, and this layer would, on accompanying them into the 

 oviduct and thence into the uterus, be converted into a common 

 chorion ; or (2) the effect may have been produced by the disappearance 

 of the granular layer of each ovule and by the subsequent investment 

 of the four fecundated ovules by a layer formed by the walls of the 

 oviduct or uterus ; — but this could not happen unless the secondary 

 (amniotic) chorion had been absorbed, or had never been formed ; or, 

 (3) the four amniotic chorions might have fused at their points of 

 contact and have undergone absorption at all but their peripheral 

 portions. 



Vitality of the Spermatozoa of the Trout. f— The details of M. 

 Henneguy's experiments will be seen by the following table, which 

 shows the number of ova that became developed after they (having 

 been impregnated), were subjected to the following agents : — 



(1) Pure water 62 eggs .. .. 50 developed. 



(2) Water with 5 per cent, alcohol .. 91 „ .. .. 7i „ 



(3) „ „ 10 „ „ .. 59 ., .. .. 50 



(4) „ „ 5 „ ether .. 51 „ .. .. 42 



(5) „ saturated with chloroform 32 ,, .. .. 19 „ 



The fishes produced exhibited no difference to those developed 

 from ova which had been fecundated in the ordinary manner ; and it 

 is concluded that doses of alcohol, &c., which are suificient to kill 

 Infusoria for instance, have no effect on the spermatozoa. 



Experiments on Development.^ — MM. Pouchet and Beauregard 

 describe some experiments in which they removed from eggs a small 

 quantity of their liquid albumen and replaced it by a certain quantity 

 (half a gramme) of sugar ; and then reclosed the eggs in the manner 

 they have already described. Experiments were made on eighty 

 eggs, and of these twenty-eight were opened during the first thirteen 



* ' Comptes Eendus,' Ixxxviii. (1879) No. 9. 

 t ' CR. Soc. Biol.' for 1877 (1879), p. 274. J Ibid., p. 338. 



