ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 561 



corresponding elements of the basipodimn. This association of certain 

 metapodials and certain basipodials is of widespread occurrence in 

 development. 



Erythroblasts of Pig* Embryo.* — Victor E. Ernmel finds that the 

 originally more or less spherical cell body changes to a flattened bicon- 

 cave disk, or even concavo-convex cup. The nuclei decrease in size, 

 become compact, tend to be flattened, and lie excentrically at one side. 

 This nuclear side tends to swing undermost. The erythroblast some- 

 times shows a small pointed cytoplasmic process projecting from the 

 surface ; it may have to do with certain conditions attending the final 

 division. 



The non-nucleated erythroblasts or plastids vary from rounded to 

 biconcave disks and cup-shaped elements. No conclusive evidence was 

 obtained indicating the origin of plastids by the extrusion of the nucleus 

 from the erythroblasts or of the disintegration of the nucleus within the 

 cell. On the contrary, a process was repeatedly observed and studied, 

 in vitro, in which there occurred a constriction of the cytoplasm in the 

 region between the nuclear and cytoplasmic poles of the erythroblast, 

 which, when completed, resulted in the division of the cell into two 

 parts, the one a nucleated structure, the other a non-nucleated ha?mo- 

 globin-containing corpuscle. In the embryo corroboration of this 

 process of cytoplasmic constriction was obtained. In brief, as against 

 the prevalent views of nuclear extrusion and intracellular disintegration, 

 the author upholds the view that non-nucleated erythrocytes arise by a 

 process of cytoplasmic constriction. 



Foetus of Sperm Whale.t — Frank E. Beddard has studied a foetus 

 of Physeter macrocephalus, and attention may be directed to a few of 

 his results. The form is very markedly piscine, the characteristic and 

 enormous head of the adult being not at all conspicuous. Indeed the 

 head was roughly only one-fourth of the total body-length. A very 

 interesting point is the presence of what appear to be two nostrils, that 

 on the right-hand side (which disappears) being rather shorter and 

 shallower. The relative smallness of the lung is commented on, and the 

 observer discusses a body which he interprets as a second lung lobe. 

 The remarkable fixed looping or festooning of the small intestine is 

 described. 



Correlation between Egg-laying and Yellow Pigment in Fowl.} 

 A. F. Blakeslee and D. E. Warner bring forward dnta which indicate a 

 connexion between the amount of yellow pigment showing in a hen and 

 her previous laying activity. The most natural assumption is that 

 laying removes yellow pigment with the yolks more rapidly than it can 

 be replaced by the normal metabolism, and in consequence the ear-lobes, 

 the be:ik and the legs become pale by this subtraction of pigment, it 

 is true that environmental factors may influence the yellow pigmentation, 

 and sickly birds may be pale though not in a laying condition. But, in 



* Amer. Journ. Anat., xvi. (1914) pp. 127-204 (5 pis.). 



t Ann. Durban Museum, i. (1915) pp. 107-24 (1 pi. and 9 figs.). 



% Amer. Nat., xlix. (1915) pp. 360-68. 



