462 H. L. WIEMAN 



the growth period of the spermatocyte the nucleus contains two 

 chromatin nucleoh of unequal size, and occasionally other small 

 nucleolus-like granules which have no constancy in their pres- 

 ence, size or relationship. When the spindle of the first sperma- 

 tocyte forms, the chromatin nucleoli appear as accessory chro- 

 mosomes, together with ten bivalent chromosomes. The two 

 accessories pass undivided to one pole of the spindle considerably 

 in advance of the other chromosomes, with the result that one- 

 half of the daughter cells in this division receive twelve, and the 

 other half, ten univalent chromosomes. Since all the chromo- 

 somes divide in the second spermatocyte division, one-half of the 

 total number of spermatids receive twelve, and the other half, 

 ten univalent chromosomes. 



Gutherz ('12) working over the same ground, disagrees with 

 Guyer's interpretation of the two chromatin nucleoli appearing 

 in the resting nucleus of the spermatocyte. Gutherz finds at this 

 stage in addition to several (1 to 3) true nucleoli, a basophil nuc- 

 leolus composed of a pair of chromosomes which at times assumes 

 a quadripartite form. This tetrad-like appearance he takes to 

 indicate a subsequent separation in both maturation divisions, 

 which means an equal (quantitative) distribution of chromosomes 

 to all spermatids. Gutherz does not describe the meiotic divi- 

 sions, nor does he commit himself on the chromosome number. 

 In his figure 10, of a first spermatocyte metaphase, twelve bodies 

 may be counted, but it is by no means certain that they all repre- 

 sent single chromosomes. He seems inclined to accept the 

 results of Duesberg and of Branca (whose paper is not available 

 to me at the present time), both of whom give twenty-four as 

 the unreduced number. 



The unanimity of all recent work in settling on twenty-four, 

 or a number very close to it (Guyer, 22 in the male), as the dip- 

 loid number, is seriously disturbed by the results of Winiwarther 

 ('12) who reports the finding of forty-seven chromosomes in the 

 spermatogonia. According to him, the metaphase of the first 

 spermatocyte shows twenty-four chromosomes, one of which is a 

 heterochromosome that later passes undivided to one pole of 



