966 MR. R. I. rococK on the [June 14, 



Genus Euceuvus Gray. 



EUCERVUS HEMIOXUS Raf. 



(The Mule Deer.) 



Notbin,2ri ^(^ fi^i' •'^-'^ I in» Mw.tre, is known of tlie strnctureof the 

 feet ; but the preoi-bital, tur.sjil, and metatarsal glamls are present, 

 the metatarsal gland Ijeing unique in its length, since it extends 

 at least halfway down the cannon-bone towards the fetlock. This 

 character I have used as a generic feature to distinguish Eiccervus 

 from JJorcelaphiis (p. 971). 



Genus Blastocerus Sund. 



Bl.\STOCERUS DICHOTOMUS 111. ( = PALUDOSUS). 



(The Marsh-Deer.) 



The preorbital and tarsal glands are present aiid the metatarsal 

 gland absent, according to Mr. Lydekker. In this last- mentioned 

 character the Marsh-Deer resembles Alazama. 



Blastocerus bezoarticus Linn. ( = campestius). 

 (The Pampas Deer.) 



This species appears to resemble the foregoing in the nature 

 of its glands. 



The difference in the antlers suggests that this Deer should 

 rank as a genus (or subgenus) distinct from B. dichoioiiius. 



Genus llirrocAMELUS Leuck. 



HiPPOC'AMELUS BISULCUS Mol. 



(The Chilian Guemal.) 



Under the name Xenelaphics, Mr. Lydekker admits this and 

 its ally //. aiitisiensis as a subgen\is on account of the simply 

 forked antlers, the coarse brittle hair, and the absence of the 

 metatarsal gland. The latter, however, is also wanting in 

 Blastocerus and Jfazcona, leaving the subgeneric status dependent 

 on the character of the coat and antlers. This author also I'emarks 

 that the simple form of the antlers is seemingly due to degra- 

 dation and cannot therefore be regarded as an ancestral type, 

 becjiuse the absence of spots in the fawn and the suppression 

 of the metatarsal gland are obviously specialised features. Yet 

 there is no commoner morphological phenomenon than the 

 association of primitive with specialised features in a species. 

 Moreover, the nutleis oi IlippocconelKs and Mazama may be due 

 to simplitication from a much more complex type and yet be 

 " ancestral " in the sense that their characters residt fx-om the 

 retention to maturity of an early growth- stage. 



