SPERMATOGENESIS OF THE CHICKEN 69 



3. It is still present in too few cells, if it should be interpreted 

 as one of those rare cases where the odd chromosome divides in 

 either the I or II spermatocyte division. 



4. It varies in shape. 



5. It varies in size. 



6. It varies in number. 



7. In no single cell is it of such a shape or size, or in such a 

 position, that it could not readily be interpreted as anything 

 else than an X-chromosome. 



LITERATURE CITED 



Bateson, W., and Punnett, R. C. 1911 The inheritance of the peculiar pig- 

 mentation of the Silky Fowl. Jour. Genetics, vol. 1, pp. 185-203. 



Boring, A. M. 1907 A study of the spermatogenesis of twenty-two species of 

 Membracidae, etc. Jour. Exp. Zool., vol. 4, p. 469. 



1913 The chromosomes of the Cercopidae. Biol. Bui., vol. 24, p. 133. 



Bridges, C. B. 1913' Partial sex-linkage in the pigeon. Science, N. S., vol. 37, 

 pp. 112-113. 



Cole, L. J. 1912 A case of sex-linked inheritance in the domestic pigeon. Sci- 

 ence, N. S., vol. 36, pp. 190-192. 



Davenport, C. B. 1906 Inheritance in poultry. Carnegie Inst., Washington, 

 Publ., No. 52. 



1911 Another case of sex-limited hei'edity in poultry. Proc. Soc. Exp. 

 Biol. Med., vol. 9, pp. 19-20. 



1912 Sex-limited inheritance in poultry. Jour. Exp. Zool., vol. 13, 

 pp. 1-18. 



Durham, F. M., and Marryatt, D. C. E. 1908 Notes on the inheritance of 

 sex in canaries. Rep. Evol. Comm. 4, p. 57. 



Edwards, C. L. 1910 Idiochromosomes in Ascaris megalocephala and Ascaris 

 lumbricoides. Arch. f. Zellforschung. Bd. 5, p. 422. 



Goodale, H. D. 1909 Sex and its relation to the barring factor in poultry. 

 Science, N. S., vol. 29, pp. 1004-1005. 



1910 Breeding experiments in poultry. Proc. Soc. Exp. Biol. Med., 

 vol. 7, pp. 178-179. 



1911 Studies on hybrid ducks. Jour. Exp. Zool., vol. 10, p. 241. 



GxJYER, M. F. 1900 Spermatogenesis of normal and of hybrid pigeons. Chicago. 

 1909 a Spermatogenesis of the domestic guinea. Anat. Anz., Bd. 34, 

 p. 502. 



