The Growth Cycle of Deer Antlers 183 



upon differentiation of the antlers and gonadal function 

 (pre-mature shedding of the velvet and rut) and the growth- 

 stimulating effect of increase of light by the subsequent 

 resumption of antler growth. 



REFERENCES 



Aub, J. G. (1940). Unpublished communication. 



Aub, J. G., Wislocki, G. B., and Waldo, C. M. (1950). New York State 



Conservationist. Reprint No. 98. 

 Bernhard, K., Brubacher, Z., Hediger, H., and Bruhin, H. (1953). 



Experientia, 9, 138. 

 Caton, J. D. (1877). The Antelope and Deer of America. Cambridge, 



Mass.: Hurd and Houghton. 

 Gruber, G. B. (1937). Ges. Wiss. Nachr. Biol., 3, 9. 

 Jaczewski, Z. (1952). Acta physiol. polon., Prace III, 201. 

 Nitsche, H. (1896). Studien iiber Hirsche. Leipzig. 

 Rorig, A. (1899). Arch. EntwMech. Org., 8, 382. 

 Rorig, A. (1907). Arch. EntwMech. Org., 23, 1. 

 Tandler, J. (1910). Anz. Akad. Wiss., Wien, 47, 252. 

 Tandler, J., and Grosz, S. (1913). Die biologischen Grundlagen der 



sekiindaren Geschlechtscharaktere. Berlin: Springer 

 Waldo, C. M., and Wislocki, G. B. (1951). Amer. J. Anat., 88, 351. 

 Waldo, C. M., Wislocki, G. B., and Fawcett, D. W. (1949). Amer. J. 



Anat., 84, 27. 

 Wislocki, G. B. (1943). Essays in Biology, p. 631. Univ. of California 



Press. 

 Wislocki, G. B. (1949). Endocrinology, 44, 167. 

 Wislocki, G. B., Aub, J. G., and Waldo, C. M. (1947). Endocrinology, 



40, 202. 

 Wislocki, G. B., and Singer, M. (1946). J. comp. Neurol., 85, 1. 

 Wislocki, G. B., and Waldo, C. M. (1953). Anat. Rec, 117, 353. 

 Wislocki, G. B., Weatherford, H. L., and Singer, M. (1947). Anat. 



Rec, 99, 265. 

 Zawadowsky, M. M. (1926). Trans, exper. Biol. Zoopark Moscou, 1, 18. 



DISCUSSION 



Bourliere: Prof. Wislocki, what is the influence of the age of the 

 animal on the antler cycle? Is the cycle modified in any way in the 

 very old animals? 



Wislocki: Senescent changes do occur in deer antlers as revealed by 

 observations on the antlers of old deer and, particularly, by several 

 series of shed antlers which have been collected annually from captive 

 deer. These series reveal a progressive annual increase in size and weight 

 of the antlers up to 8 or 9 years of age, after which there is a rapid 



