890 SIR V. BROOKE ON THE [Nov. 19, 



The question as to whether these minor groups should be re- 

 garded as genera or subgenera, or merely marked as nameless sections, 

 appears to me to be of wholly secondary importance. 



Actuated by this belief, I have retained the names originally given 

 to these subgroups whenever the grouping has appeared to me to 

 be natural, and have spoken of them as subgenera. The characters 

 upon which the subgenera are based are derived principally from the 

 form of the antlers, the skull, the rhinarium 1 , external coloration, 

 position and degree of development of the cutaneous glands, and 

 general external form. 



As is the case with the family characters, it is seldom that any 

 one subgeneric peculiarity can be taken singly as exclusively charac- 

 teristic of a certain subgenus ; but the existence in different fixed 

 combinations of these characters in the several subgenera is an 

 empirical certainty. For example, the form of rhinarium peculiar to 

 Rusa (vide infra) is shared by other groupSj but never in combina- 

 tion with the form of antler and immense lacrymal pit typical of 

 that subgenus; and no species of Rusa is without this combination. 

 Again, the form of the rhinarium in the subgenus Cervus differs 

 from that of Rusa, but resembles that of Dama &c. ; but in 

 Cervus this rhinarium is always associated with the antlers typical 

 of that subgenus, and an anal disk of paler colour than the adjacent 

 parts surrounding the tail ; whilst in Dama it is combined with the 

 palmated form of antler and tuft of long hair surrounding the 

 prepuce. It is needless here to give further examples of this law : 

 it will be found fully illustrated in the diagnoses of the subgenera 

 (imperfect as these doubtless are) given in the synopsis. 



The objection that antlers are absent in the females of all existing 

 species with the exception of JRangifer, whilst in Hydropotes they 

 are wanting in both sexes, has been frequently urged against the 

 value of characters based on these appendages. The stability of 

 this objection strikes me as very questionable. There can be no 

 doubt that it would be highly convenient if such prominent and 

 easily observed features as those afforded by the antlers were univer- 

 sally attainable ; and the lack of their invariable occurrence is 

 doubtless a source of some slight confusion to the systematist. 



But surely the value of a character as a test of genetic affinity 

 cannot be judged upon utilitarian principles ; and if, as I think, I 

 can show reason for believing the form of the antlers is one of the 

 clearest proofs of the blood-relationship of the species contained in 

 the various subgenera, characters derived therefrom must be regarded 

 as the most trustwothy for taxonomic purposes. 



In order to account for the phenomena presented by the antlers 

 in the males of the existing Deer, four factors are necessary : — 

 (1) The gradual evolution of the antlers from very simple to complex 

 forms; (2) Their constant tendency to vary ; (3) Variation extend- 

 ing far enough to induce the partial atrophy of one part of the antler 



1 I follow ITLiger and Sundevall in the adoption of this term for the naked 

 moist skin between the nostrils. It is decidedly preferable to muffle, which is 

 French, or muzzle, which signifies something quite different in every-day speech. 



