634 Growth o£ Deer Antlers 



masses situated on either side of the base of the bladder, compactly ensheathed 

 by connective tissue, and varying from 2 to 4 cm. in length and about 1 cm. in 

 diameter, depending on their fvuictional condition. In the June and July ani- 

 mals (pi. 2, figs. 5 and 6) the seminal vesicles are minimal in size; in the August 

 animal (pi. 2, figs. 7 and 8) they are distinctly enlarged; while in the October 

 specimens (pi. 3, figs, g and 10) they are about twice the size of the June glands. 

 The histology also undergoes a marked change. In the June and July specimens 

 (pi. 2, figs. 5 and 6) the gland presents numerous small cavities lined by rela- 

 tively low, inactive cells. The connective-tissue partitions between the glandu- 

 lar spaces are relatively thick. Very characteristic of these months is the 

 presence in the lumina of darkly pigmented, amorphous masses which give the 

 impression of being inspissated secretion. In August (pi. 2, figs. 7 and 8) the 

 lumina are distinctly enlarged and the epithelial cells lining the mucous mem- 

 brane are considerably taller than in June and July and show signs of secretory 

 activity. The black, amorphous masses of secretion have diminished. By Oc- 

 tober (pi. 3, figs. 9 and 10) the gland is markedly changed, its cavities having 

 become very much enlarged and filled with copious amounts of globular and 

 granular secretion. Accompanying this enlargement, the partitions separating 

 the numerous cavities have become stretched, transforming the mucous mem- 

 branes into an intricate system of trabeculae or septa. The epithelial cells have 

 become exceedingly tall and slender, with the nuclei pushed to the bases of 

 the cells. From an average height of around 18 to 20 /a in June and July the 

 cells have attained a height of about 40 ^a. None of the black, amorphous, in- 

 spissated inasses of the preceding stages are present any longer. 



From these observations it may be concluded that the seminal vesicles, as 

 well as the testes, of the Virginia deer undergo pronounced seasonal variations. 

 Both the testes and seminal vesicles which are in a state of regression in May 

 and June become gradually activated, to reach a maximum state of activity in 

 the fall, when rutting occurs. It is known that in other mammals the male ac- 

 cessories are maintained by the male sex hormone produced by the testes; 

 consequently, it seems fully justifiable to relate the seasonal activation of the 

 seminal vesicles, shown here in the Virginia deer, to a seasonal activity of the 

 testes. One may deduce that the testes of the Virginia deer begin to become 

 active late in June, and that they in turn begin to stimulate the male acces- 

 sories in July until these reach their maximum activity, together with the 

 gonads, during the fall rutting season. 



The Effects of Castration on the Groivth and Periodicity of the Antlers. The 

 periodicity of the gonads and seminal vesicles invites comparison with the 

 antlers, a male secondary sex character which is also subject to seasonal 

 changes. In a separate paper the writer" has described the annual cycle of the 

 deciduous antlers of the Virginia deer, based upon a study of the same animals 

 utilized in the present report. Briefly stated, the antlers of the white-tailed 

 deer commence to grow late in April or early in May; they attain their full 



