294 THEOPHILUS S. PAINTER 



The first spermatocyte cells show (text fig. 1, B and D) six 

 large macro-chromosomes and from eight to eleven micro- 

 chromosomes. Here, again, we can easily identify the 'b' and 

 'c' chromosomes, but the ' a' element is not so easily distinguished. 

 A bipartite chromosome is also seen in such a view. No side 

 views of the spindles are shown, but the two late anaphase 

 stages represented in text figure 1, C and E, show what takes 

 place in this division; the lower pole of each cell shows five macro- 

 chromosomes, while the upper pole shows six large bodies. The 

 extra element (marked X) appears sometimes as quadripartite 

 (text fig. 1, C), sometimes as a bivalent chromosome (text 

 fig. 1, E). 



No study of dividing second spermatocytes was made. Judg- 

 ing, however, from the anaphase stages of the first division, half 

 of the secondary spermatoctes should carry five and half should 

 carry six chromosomes, the extra element being the X-chromo- 

 somes. In this respect, S. undulatus consobrinus is like Anolis 

 and S. spinosus. 



Spermatogenesis of Holbrookia texana 



This 'zebra-tair lizard has not proved a very satisfactory 

 form for study, because the testes, in my experience, are difficult 

 to preserve well and the sex-chromosome rarely shows up in 

 side views of the first maturation spindle; that is, it rarely passes 

 to one pole of the cell before the autosomes divide. Spermato- 

 gonial division stages are rare in my preparations, but favorable 

 plates (fig. 37) show an outer circle of V-shaped macro-chromo- 

 somes, while within the micro-chromosomes are found. A 

 close inspection of figure 37 will show the presence of three pairs 

 of macro-chromosomes which are distinctive because of their 

 size. These are labeled 'a,' 'b,' and 'c,' just as was done for 

 the other lizards studied. The micro-chromosomes do not show 

 up well in figure 37. 



In equatorial plate view the first maturation spindles show 

 six macro-chromosomes and about twelve or thirteen micro- 

 chromosomes (figs. 38 and 39). There is a marked tendency 



