ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 189 



medullary groove, of notochord apparently from mesoblast, of proto- 

 vertebra3, &c, are described. In regard to tbe notocbord and tbe 

 destiny of tbe primitive streak, Haswell substantially agrees with 

 Kolliker. In describing later stages, tbe appearance of tbe neurenteric 

 canal is specially noticed. 



Fate of the Blastopore in Amphibians.*— Dr. F. Schanz finds that 

 in Triton tseniaius and Rana temporaria tbe blastopore becomes narrowed 

 by tbe approximation of tbe lateral lips of tbe orifice. In Triton two 

 orifices appear, one of wbicb becomes tbe neurenteric canal and the 

 other the anus. In the frog there is only one orifice, the place of tbe 

 other being taken by a pit, which, later on, opens into the rectum ; the 

 cause of this is the rapid growth of the medullary folds, and the anus 

 is not a neomorph. The oblique direction seen in the frog is due to tbe 

 growth of the tail ; the neurenteric canal really exists even if it has no 

 distinct lumen, such as is later seen in the frog. These results are by 

 no means in agreement with those lately arrived at by Prof. Kupffer. 



Spermatogenesis of Salamander.f — Prof. W. Flemming has re- 

 directed his attention to the sj:>ermatogenesis of Salamandra maculata, 

 which be first investigated in 1880. His chief results are as fellows : — 

 (1) The bead of the sperm of Urodela is formed from tbe entire 

 chromatin of the spermatide nucleus. (2) The formation of the stain- 

 able head-process is associated with gradual thickening and elongation 

 of the nuclear network. (3) Young forms freed from their natural 

 surroundings contract in a curious fashion. (4) One end of the sper- 

 matide nucleus is from the first thicker in its elongation, and forms 

 the posterior (tail) end of the head. (5) The rudiment of the achro- 

 matic middle portion is at first to some extent chromatic, and therefore 

 nuclear. (6) The tail filament can at first be traced through the centre 

 of the middle portion to the base of the head. It is also probably from 

 the nucleus. (7) In their stage of elongation the spermatides include 

 nucleoli, but these appear to have no morphological role. (8) Tbe 

 spermatogenesis progresses in a testicular lobe from one end to tbe 

 other. (9) Before the beginning of spermatogenesis, the spermatocyst 

 is seen to include a cavity which moves to the foot of the cyst. Pound 

 this the spermatide nuclei or cells become regularly disposed. (10) 

 The space includes chromatophilous granules, which persist between the 

 heads of the spermatides. (H) The heads of the perfectly mature 

 sperms are distinguishable by the peculiar brown colour assumed on 

 staining with safranin. (12) Wiedersperg's conclusions rest on misinter- 

 pretation. 



Germinal Layers in Teleostei.}— Hr. G. Brook gives an account of 

 the structure of the ripe unfertilized ovum of the herring, of the early 

 stages in development, and particularly of the relation of the parablast 

 (subgerminal free nucleated layer) to the yolk and to the embryo. In 

 describing the structure of the ripe ovum not much that is new is 

 recorded ; the author unites the descriptions of Kupiier and Hoffmann, 

 and corroborates both in reconciling them. The ovum is an ideal nieso- 

 blastic type. Before the first furrow appears the egg is made up as 

 follows : — (1) Of a large collection of protoplasm in the germinal area 



• Jenaisch. Zeitschr. f. Naturwiss., xxi. (1887) pp. 411-21 (1 pi.), 

 t Arch. f. Mikr. Anat., xxxi. (1S87) pp. 71-97 (1 pi.). 

 X Trans. Roy. Soc. Edm., xxxiii. (1887) pp. 199-239 (3 pis.). 

 1888. P 



