1915.] Allen, American Deer of the Genus Mazama. 529 
in others comparable with them in age and sex. It is evident, however, that 
age influences to some extent the size and shape of the vacuity through the 
gradual extension of the margins of the bones that form its boundaries, as 
the lacrymals, the nasals especially, and to a less extent the frontals and 
maxillaries, the size of the fossa thus tending to decrease with progress 
toward senescence. Thus in specimens of the same species the size of the 
lacrymal vacuity may be two or three times larger in some than in others. 
The premaxillaries, in specimens of the same species, may present a 
broad junction with the nasals (in one case for a space of 10 mm.) or merely 
meet them (as in about 50% of the Santa Marta series), or terminate 2 or 3 
to 10 mm. below them. In some species (of each color group), in which the 
number of specimens available for examination is small, the normal condi- 
tion seems to be complete junction of the premaxillaries with the nasals. 
The lacrymal pit also proves to be a highly variable character, being 
sometimes deep and well-defined and sometimes indistinct or nearly obso- 
lete in specimens of the same subspecies. 
It is therefore evident that the relative size and form of the nasals, the 
size and contour of the antorbital vacuity, the junction or otherwise of the 
premaxillaries and nasals, and the depth of the lacrymal pit are extremely 
untrustworthy as diagnostic characters, although they often enter into the 
diagnoses of species and subspecies. 
Species and Subspecies. With the present lack of material available in 
even the largest museums, the discrimination of species and subspecies of 
the Mazama group must depend largely upon the experience and point 
of view of the describer with respect not only to the importance and prob- 
able constancy of the differences noted but also the geographical conditions 
involved. For example, Mazama rufina of Mount Pichincha in Ecuador 
and M. brincenw of the paramo of the Sierra de Merida in Venezuela so 
closely resemble each other in size, in coloration, and in the peculiar charac- 
ter of the pelage, that if their known ranges were contiguous they would 
naturally be regarded as local forms of a single species, but their wide 
separation by regions of much lower elevation and very different climatic 
conditions renders improbable any continuous distribution and consequent 
geographical intergradation. On the other hand four forms of red brocket 
are recognized in the present paper from Ecuador alone, one of which is 
from the paramo of Mount Pichincha and one from the tropical coast 
district. One of the others is from the eastern slope of the Andes, the other 
from the western. Three of them are large forms, some of which, or perhaps 
all, may be found to intergrade when material in proper amount becomes 
available from intermediate points. In this case, as with most of the other 
forms here recognized, it seems best to treat them nomenclatorially as full 
