240 SIDNEY I. KORNHAUSER 



chromosomes, being purple in crystal violet + alizarin, and red 

 in methyl green + acid fuchsin. The use of these stains enables 

 one to establish the number twenty-five for the spermatogonial 

 chromosomes. As will be shown later, twenty-two of these are 

 autosomes, two form an x-complex, and one is a y-chromosome. 

 The male somatic number was likewise established by the study 

 of serial sections of embryos in which many counts of single 

 individuals were made. Figures 13 to 16 (Plate XXIV) are typical 

 25 chromosome plates of such male embryos. The following 

 important variation, the only characteristic one so far found in 

 the study of Anisolabis, must be noted. In male embryos, with 

 typical 25 chromosome cells, one finds clear metaphase plates 

 with only 24 chromosomes. This happened too often to be purely 

 accidental or due to error or oversight. A probable explanation 

 of the phenomenon will be given in Part 8. 



6. THE SPERMATOCYTE CHROMOSOMES 



The initial and most fundamental facts to be established were 

 that twelve chromatic elements were uniformly present in prim- 

 ary spermatocyte metaphase plates (Plate XXV, figs. 28-29), and 

 that half the secondary spermatocytes possessed twelve chromo- 

 somes and the other half had thirteen (Plate XXVI, figs. 44-47). 

 These facts made necessary the careful study of the origin of 

 the twelve primary spermatocyte chromosomes. 



From the 25 spermatogonial chromosomes are formed eleven 

 autosomal tetrads and a heterochromosomal hexad, which I 

 have called the xxy-complex and which may be seen in figures 

 17-27 (Plate XXV). The autosomal threads and tetrad forma- 

 tion are omitted from these figures. The evidence is rather clear 

 that the tetrads are formed by parasyndesis, and it is hoped that 

 additional smear preparations will enable the author to deal 

 with this point in more detail in another paper. Figures 17-22 

 show merely the nuclear outline and the xxy-complex, stained in 

 iron-haematoxylin, the relative intensity of the stain being 

 depicted as accurately as possible in the figures. 



Figure 17 is an early leptotene stage, the autosomal threads 

 just emerging from the telophase chromosomes of the ultimate 



