No. 2.] THE EGG OF BUFO LENTIGINOSUS. 30 1 



A and B) ; but at this period there is never found a paired 

 arrangement of all of the chromosomes which is so character- 

 istic of a later stage in the egg of Bufo, as well as in the ^g-g 

 of Triton, Axolotl, and the selachian. 



In some sections it is easy to follow the entire course of one 

 or two individual chromosomes, so that there can be no doubt 

 that the chromatin is in the form of distinct rods and not in a 

 continuous skein ; but as the chromatin stains very faintly at 

 this stage, and as most of the chromosomes are so long and 

 closely interwined that it is impossible to distinguish between 

 them, I have been unable to count their number satisfactorily. 

 In some cases there appear to be fourteen or sixteen of these 

 chromatin threads ; in others, at least twenty. I have not 

 been able to make out definitely a higher number, yet presum- 

 ably there are twenty-four chromosomes present, as that is the 

 number which is found at the end of the hibernation period. 



The chromosomes occasionally appear to end in small round 

 homogeneous balls greatly resembling the smaller nucleoli 

 (Fig. 5, A, B, and C). Whether these bodies are nucleoli with 

 which the chromatin threads have come in such close contact 

 that the two appear to be united, or whether they are rounded 

 masses of fused chromatin microsomes, I have been unable to 

 determine. 



The membrane of the germinal vesicle never has a perfectly 

 smooth contour, but is decidedly wavy, showing a number of 

 small projections and indentations. This form of outline is 

 considered by many investigators to indicate that the vesicle 

 leaves the center of the egg and migrates towards the upper 

 pole by amoeboid movements. While in the Axolotl, frog and 

 newt the germinal vesicle reaches the periphery of the Qgg 

 before disintegrating, in Bombinator igneus, according to 

 Goette ('75), and in Bufo lentiginosus, dissolution begins when 

 the vesicle is but little more than halfway between the center 

 and the periphery. As there is subsequently a flowing of the 

 nuclear substance to the upper pole of the egg (PI. XXIX, 

 Figs. 17, 19), which obviously cannot be due to amoeboid 

 movements, I am inclined to believe that the early eccentric 

 movement of the vesicle, as well as the later migration of its 



