566 * FERNANDUS PAYNE 



if one divides and the other passes to one pole undivided, one 

 cell will receive 12 and the other 13 chromosomes; if one passes 

 to one pole and the other to the second pole undivided, each 

 resulting cell will receive 12 chromosomes; lastly, if both single 

 chromosomes pass to one pole undivided the result is one cell with 

 11 chromosomes and one with 13. Cells with 14 chromosomes 

 are rather rare and, as shown above, are composed of ten bivalent 

 and four univalent chromosomes. The irregular division of 

 these four chromosomes might cause the variations, ranging from 

 10 to 14, the munber which Carnoy ('85) actually described. 

 Unfortunately my material does not show sufficient anaphases 

 to demonstrate the distribution of them. 



There is a short resting stage between the first and second 

 maturation divisions (fig. 3, A). In the anaphases of the second, 

 some of the -cells show lagging chromosomes. While the evi- 

 dence is not direct, these lagging chromosomes are no doubt the 

 univalent ones which behave irregularly in the first maturation 

 division. Judging from such figures as 3, M, N, 0, and P, here 

 again the behavior is irregular, and the spermatids undoubtedly 

 receive numbers varying from 11 to 14 and perhaps from 10 to 

 14 chromosomes. All of these spermatids, I believe, develop 

 into mature spermatozoa, as I have seen no sign of their degenera- 

 tion. Whether all such spermatozoa function is impossible to 

 say with the limited amount of material at my command. I hope 

 to be able in the near future to obtain additional material for the 

 study of this and other questions which remain unsolved. 



A few words concei*ning the growth period may not be out of 

 place before leaving this specimen, as it seems to be clearer here 



Fig. 4 Specimen 29-3. A, B, spermatogonia! cells with 24 chromosomes each; 

 C, D, oogonial cells which have been included in this plate and which were the 

 only ones which could be counted, 25 chromosomes (They were not very clear and 

 I lay no weight on this evidence) ; E, F, G, serial sections, side view, of a metaphase 

 plate of the first division with 13 chromosomes showing 11 bivalent and two uni- 

 valent; I, J, K, serial sections of a metaphase plate with 12 chromosomes, all of 

 which are bivalent; H, metaphase plate, pole view, first division, 12 chromosomes; 

 L, metaphase plate, 13 chromosomes; M, N, 0, anaphases of the first maturation 

 division showing distribution of the univalents; P, Q, second spermatocyte divi- 

 sions, metaphase plates, 13 chromosomes; It, S, the same with 12 chromosomes. 



