370 SUMMARY OF CURRENT RESEARCHES RELATING TO 



nephric groove was converted into a canal, which, becoming separated 

 from the overlying epiblast, might sink into the deeper-lying parts of the 

 body. We are justified in assuming the persistence of the blastopore as 

 the anus in early Chordata ; thus, if the nephric groove were continued 

 round to the anus, it would practically open into the extreme hinder end of 

 the mesenteron, in other words into the urodseum (Gadow). Probably 

 about the same time that the nephric groove was being converted into the 

 nephric canal (segmental duct) the proctodfeum was being invaginated. 

 The latter would push before it the posterior orifice of the nephric canal. 

 The nei)hridia themselves appear to be of mesoblastic origin. On the 

 hyiiothesis just sketched out, the nephridia always open by their original 

 epiblastic pores — primitively, directly to the exterior ; secondarilj-^, into a 

 canal separated from the epiblast : also the archinephros could be equally 

 effectively functional throughout the whole period of its modification. 



Embryogeny of Anthropoid Apes.* — Dr. J. Deniker has been able to 

 study the fcetus of the gorilla and the gibbon, which he compares with that 

 of man. Especial attention is given to the proportions of the limbs, and it 

 is shown that while in man, during the earlier stages of embryonic life, the 

 lengths of both extremities are almost equal, in the anthropoid apes, at 

 even an early period, the length of the upper exceeds that of the lower 

 limb. The frontal region of the skull ossifies more rapidly, and the 

 occipital and petromastoid portions more slowly in anthropoid apes than 

 in man. The encephalon of the foetal gorilla weighed 28 grammes, or one 

 sixteenth of the weight of the whole body ; in both foetus the cerebellum 

 was very small and completely covered by the cerebrum. The relative 

 and absolute dimensions of the brain of the foetal gorilla correspond to 

 those of the human foetus at the fifth month, but in its convolutions it was 

 equivalent to those of the human foetus at the sixth month. The dentary 

 follicles of both gorilla and gibbon are developed earlier than in man ; in 

 the gorilla the teeth of the upper appear before those of the lower jaw, or 

 in the reverse order to what ordinarily obtains in man. The cascal 

 appendage appears to increase relatively to age in the gorilla, while the 

 contrary is the rule in man. 



Segmentation of Frog Ova in Sublimate Solution.j — Herr T. Dewitz, 



in reference to a report by Tichomirofi" as to parthenogenesis artificially 

 induced in the eggs of Bombus by mechanical and chemical ii'ritation, 

 notes that he observed unfertilized frog ova to undergo segmentation in 

 sublimate solution. In some cases one segmentation has occurred, in 

 others several ; in some cases irregularly, in others normally. The ova 

 experimented on were those of JRana fusca, R. esculenta, and Hyla arhorea. 

 The segmentation occurred alike when the ova were left in the solution, or 

 simply dipped in it for a few minutes and then put into water. In the 

 latter case the segmentation became slowly evident, so that the suggestion 

 of its having been 2)reformed is not adequate. No spontaneous segmenta- 

 tion has been observed, so that if the observations be correct the sublimate 

 acts as a stimulus. 



Hybridization between Amphibia.l: — Prof. G. Born has continued his 

 researches on the hybridization of Amphibia, and after a long series of 

 experiments has reached a number of interesting results. 



(1) Crossing is possible in many cases, in three cases reciprocally. The 



* ' Recherchcs anatomiqura et cmbryologiques sur Ics Singes Authropoidcs,' Paris, 

 1885. Sec Nature, xxxv. (1887) pp. 509-10. 

 t Biol. Ccntrtilbl., vii. (18S7) pj). 93-4. 

 X Arcli. f. Mikr. Anat., xxvii. (1886) pp. 192-271 (3 pis.). 



