172 MUNSON. [Vol. XV. 



mine followed with picric acid. With the double stain of 

 erythrosin and cyanin the same difference can be observed, 

 the eggs in the first stage taking the blue, those in the second 

 taking the red stain. Lithium-carmine and Lyon's blue show 

 the same peculiarity ; the eggs in the first stage, in this case, 

 taking the red carmine stain, those in the second stage taking 

 the blue. 



While this change in the cytoplasm is in progress, there is 

 a period when portions have undergone the change, while other 

 portions remain in the former condition. In such cases it fre- 

 quently happens that in haematoxylin stains, while most of the 

 cytoplasm takes a light-blue stain, round, dark-blue bodies 

 resembling nuclei are found scattered through the cytoplasm 

 (PI. XIV, Fig. 27, j.«.). These may easily be taken for nuclei. 

 They, however, disappear as soon as the critical line dividing 

 the first and second period is reached. 



I call these yolk-nuclei. 



Another class of bodies, which I shall call peripheral bodies, 

 are scarcely less puzzling when first observed. In many cases 

 during the first period in the history of the egg, deeply stain- 

 able bodies resembling nuclei are found along the extreme 

 border of the egg (PL XIV, Figs. 25, 28 ; PI. XV, Figs. 66, 

 67, 77)- They are often regularly arranged at equal distances 

 from each other, and always immediately under the surround- 

 ing tunica propria or follicular membrane. They stain deeply 

 in Ehrlich's, Delafield's, and Heidenhain's haematoxylin, as 

 well as in carmine and safranin. They do not, except in some 

 rare cases, have the clear outlines of nuclei, but seem rather 

 diffuse (PL XIV, Fig. 28). A comparison of a tangential and 

 transverse section shows them to be round discs with one 

 fiat side and one convex side, turned inward (PL XV, Figs. 79, 

 90). They are studded with regularly arranged shining dots 

 (PL XIV, Fig. 28). At the end of this period the first layer 

 of the chorion is formed. The nature of these bodies becomes 

 evident when the formation of the chorion is observed (PL 

 XIV, Fig. 25). 



The egg membrane. — During the first stage of the egg, its 

 only covering is that formed by the tunica propria, which, as 



