ANTLER-GROWTH IN THE CERVID^. 783 



point of attachment to the posterior branch being completely 

 •concealed from the external aspect in the last three stages *. 



In view of these facts, I do not think it can be doubted that 

 the anterior Inid which develops into the " subbasal snag " in 

 Odocoileus is the homologue of the anterior bud which forms 

 the brow-tine in Cervics. In that case the " subbasal snag " and 

 the "brow-tine" are homologous structures passing under different 

 names, and to state that Odocoileus has no brow-tine is merely 

 playing with terminology. 



If this interpretation of the structure of the antlers 'wiElaphurus 

 and in the species of Odocoileus above referred to be, as I believe, 

 ■correct, it shows that these two genera are widely divergent in the 

 very point upon which relationship between them has been claimed 

 to exist, and that the likeness, such as it is, between the antlers 

 of Elaphitrus and of the Mule Deer {0. hemionus), for instance, 

 which has the so-called forked antlers without a brow-tine or with 

 the mei^est vestige of it, is purely a question of parallelism in 

 development ; that is to say, it has been brought about by growth 

 and modification of fundamentally different parts of the antler. 

 In the Mule Deer the anterior branch or brow-tine is to all 

 intents and purposes suppressed, practically the whole antler 

 being composed of the posterior branch or '• beam," which is 

 highly developed and heavily tined. In Mcq^hicrus, on the 

 contrary, the principal part of the antler is composed of the 

 finterior branch or " brow-tine," which attains a large size and is 

 divided into two prongs, while the posterior branch or beam 

 remains comparatively small and slender and projects straight 

 backwards as a long often undivided prong. 



* III connection with the date of antler-change in this Stag, attention may be 

 <liiected to its approximate coincidence with that of the typical elaphine deer of the 

 Old World ; that is to say, the antlers were in the velvet during the summer mouths 

 and functional during the autumn and winter. They were shed in the early spring 

 and at the time of writing (July 3) the new antlers are nearly full-sized though still 

 in the velvet, exactljr as in our Wapiti, Red Deer, Japanese Deer, and other Old 

 World species. The same is true of a specimen of Odocoileus americanus. On 

 the other hand an example of Ilazama bricenii which shed in April 1908, and again 

 in April 1909, did not repeat the process till May 1911. He then carried a pair of 

 antlers for 25 months ; and those that started to grow in May 1911 are still on his 

 head. Thus Dr. Scharff (' Distribution and Origin of Life in America,' p. Ill) is 

 mistaken in saying that the antler-change in American deer takes place at a quite 

 •different time of year from that of Old World deer. It is well known too that the 

 time of antler-chan»e at all events in some tropical Old World deer is highly variable 

 within specific limits. For instance, one example of C. duvaucelU in the Gardens 

 regularly carries his antlers till about the end of May, while another of the same 

 species has antlers at least half their full size at that time. 



