286 THEOPHILUS S. PAINTER 



FAMILY IGUANIDAE 



Spermatogenesis of Anolis carolinesis 



Spermatogonial divisions. All of my material was from fully 

 mature testes, so that probably all dividing spermatogonial cells 

 observed would have formed primary spermatocytes. Seen 

 from the equatorial plate view dividing spermatogonia (figs. 

 1 to 3) show an outer circle of large V-shaped chromosomes 

 (macro-chromosomes) surrounding the dot-like micro-chromo- 

 somes which lie scattered about the center of the spindle. 



The macro-chromosomes lie well apart, with very little over- 

 lapping and no fusion of the elements. The V's show, typically, 

 no trace of an achromatic bridge between the two arms, although, 

 in figure 1, the 'b' chromosomes seem to indicate this. Repeated 

 counts of spermatogonial division stages, such as are shown in 

 figure 1 and 3, indicate that there are twelve macro-chromosomes 

 in every spindle. (Careful drawings of over thirty cells were 

 made, and each gave this nufnber; in addition, innumerable other 

 counts have been made, always with the same result.) While 

 the shape of the macro-chromosomes makes it somewhat difficult 

 to pair up synaptic mates, one can usually distinguish three 

 pairs, on the basis of size. Two chromosomes, labeled 'a' (figs. 

 1 and 2), are larger than the rest (best seen in fig. 2). The other 

 macro-chromosomes, labeled 'b,' are decidedly smaller than the 

 rest, while a third pair, labeled 'c,' are slightly larger than 'b,' 

 but smaller than the remaining six chromosomes, which are much 

 the same size and shape. 



The micro-chromosomes are small dot-like or, in some 

 views, very short rod-like elements, which lie well separated 

 in the center of spindles. There is some variation in the size of 

 various dots (fig. 1) and, in a general way, one can mate up 

 these chromosomes. Making accurate counts of the mmiber of 

 micro-chromosomes is made difficult because one or more fre- 

 quently lie close to a macro-chromosome, and there is always a 

 chance that one or two elements will be hidden and overlooked. 

 The full number seems to be 22 (fig. 1), although in figures 2 

 and 3 we find 21 and 20, respectively. Occasionally these small 



