Another highly-interesting fact concerning these same antlers is their gradual increase in complexity of tines and palm from the Miocene Cervus matheroni to the great Irish Elk of post-Tertiary times.
Beyond the antlers there seems to be no character of universal applicability which distinguishes the Cervidae from the nearly-related Antelopes. There are, however, a number of structural features which are nearly universally characteristic. Excepting Moschus (which Professor Garrod would not allow to be a "Deer"), no Cervine has a gall-bladder[[190]] to its liver. All Bovidae (including Antelopes) have, with the exception of Cephalophus.
A small but constant character of the Deer is the existence of two orifices to the lachrymal duct. The genus Tragelaphus alone among Antelopes shows this character.
So far as is known the placenta of the Deer has but few cotyledons, that of the Bovidae many. But not many types are known.
The navicular, cuboid and ectocuneiform are often united. This is never the case in the Bovidae.
The first and second phalanges of the lateral (imperfectly developed) digits are always present except in the Muntjacs; they are never found in Bovidae. The Deer always present a light brown to a darker brown coloration. Elaphodus michianus is almost black. There is commonly white on the under parts and beneath the short tail. Some Deer, such as the Fallow Deer, are spotted; and the young of others that are uniformly coloured when adult are spotted. In some cases a winter coat, darker than the summer coat, is developed.
Altogether some sixty species of Deer are known, of which the preponderance are Old-World forms. The Deer of the Old World are distributed among the genera[[191]] Cervus (all Europe and Asia); Cervulus, the Muntjacs (India, Burmah, China, etc.); Hydropotes (Eastern China); Capreolus (Europe and Central Asia); Elaphodus (Eastern China); there is one American Cervus, the Wapiti. The American genera are Cariacus and Pudua. The Elk (Alces) and the Reindeer (Rangifer) are circumpolar. The principal structural modification which occurs within
the family Cervidae concerns the rudimentary fifth and second toes. In Capreolus, Hydropotes, Moschus, Alces, Rangifer, and Pudua there are considerable remains of the lower parts of metacarpals II. and V.; in the other genera smaller traces of the upper ends of the same bones.
The two most abnormal genera are Moschus and Hydropotes, more particularly the former, which neither Sir V. Brooke nor Professor Garrod allow to be members of the family at all. Moschus is usually placed in a special sub-family by itself, Moschinae, the remaining Deer being referred to another sub-family, Cervinae.
Sub-Fam. 1. Cervinae.—The genus Cervus comprises rather over twenty existing species, which, except the Wapiti (C. canadensis), are exclusively Old World in distribution. The principal features of variation in the genus, in accordance with which it has been divided up into sub-genera, are (1) palmated (Fallow Deer, Dama) or non-palmated antlers; (2) adults spotted with white at all ages and seasons (Axis), or in summer only (Pseudaxis), or not at all; (3) spotted or unspotted young; (4) existence or absence of rudimentary canines in the upper jaw.