REPTILIAN SPERMATOGENESIS 315 



E a giant spfermatozoon and one of normal size are seen (the 

 tails are not indicated in the figure). The giant spermatozoa 

 tend to occur in patches. 



The author has followed in some detail the spermiogenesis in 

 lizards. It is characterized by the elimination of enormous 

 amounts of cytoplasm. An account of the process will not be 

 given, however, until mitochondrial stains have been employed. 

 At this later time it is hoped that the origin of the giant sperma- 

 tozoa can be determined. 



SUMMARY 



1. This study on the spermatogenesis o\ lizards was undertaken 

 with two points in view: first, to determine if sex-chromosomes 

 were present and, second, to see what light could be thrown on 

 the peculiar condition found by Guyer in the spermatogenesis of 

 birds. 



2. Seven species of lizards, including two families, were exam- 

 ined and their spermatogenesis reported on in this paper. 



3. In Anolis carolinensis there are twelve large V-shaped 

 chromosomes (which for convenience have been termed macro- 

 chromosomes) and about twenty-two small dot-like chromosomes 

 (called micro-chromosomes) in the spermatogonial cells. In the 

 primary spermatocytes there are six macro-chromosomes and 

 eleven micro-chromosomes. One of these macro-chromosomes 

 is bipartite in form and passes to one pole of the cell undivided. 

 As a result, the second spermatocytes are of two kinds, part with 

 five and part with six macro-chromosomes. The sperm are 

 dimorphic as regards this bipartite chromosome, which has been 

 identified as the sex-chromosome. As far as could be determined, 

 the small micro-chromosomes were equally distributed in both 

 of the maturation divisions. 



4. The spermatogenesis of Sceloporus spinosus was found to 

 be essentially like that of Anolis. There are twelve macro- 

 chromosomes and ten micro-chromosomes in spermatogonia. 

 In first spermatocytes there are six and five of these bodies, 

 respectively. The X-chromosomes are frequently seen passing 



