164 
6. Trocuitus (——?) NIVEOVENTER. 
Crown of the head and back of the neck bronzy green; back rich 
coppery bronze; wings purple-brown ; upper tail-coverts reddish 
purple ; tail purple-black ; throat resplendent green ; abdomen snow- 
white; flanks green; under tail-coverts greenish brown, margined 
with white ; bill black, except the basal three-fourths of the lower 
mandible, which are fiesh colour. 
Total length, 3 inches; bill, 2; wing, 24; tail, 1. 
Hab. Near David; warm countries of Veragua. 
Remark.—Nearly allied to T. Edwardi and T. erythronotus ; from 
the former, however, it differs in the colour of the tail, and from the 
latter in the white colouring of the breast. 
July 9, 1851. 
John Gould, Esq., F.R.S., in the Chair. 
The following papers were read :— 
1. ON THE GENERIC SUBDIVISION OF THE Bovip#, oR HoLtow- 
HORNED Ruminants. By H. N. Turner, Jun. 
In the series of observations upon the Ungulate Mammalia, of which 
I attempted last winter to lay before the Society the more general re- 
sults, my attention was also in some measure directed towards the de- 
tailed arrangement of those portions of the order which have gene- 
rally proved subjects of difficulty. Of these, the classification of the 
Bovide, or hollow-horned Ruminants, has certainly been the greatest, 
since they form a well-marked natural group, including a great variety 
of forms, with but few remarkable differences of structure. I soon 
found, however, that even setting aside some of the more strikingly- 
modified genera, the distinctions afforded by the skull were much 
more decided than any that I could find among the Cervide, which, 
from their being less rich in number and variety, were always easier 
to subdivide correctly. Not having been able at that time to observe 
the skulls of certain of the more remarkable forms, I set the matter 
aside for better opportunities ; and now that the large and interesting 
collection of hunters’ spoils which Mr. Roualeyn Gordon Cumming 
has brought together, and is at present exhibiting in London, has 
given me the opportunity of supplying some of these desiderata, I 
venture, although there are yet a few points I could wish to ascertain, 
to lay this portion of my researches before the Society. 
There cannot be a doubt that the horns present the best and most 
readily discernible characters, or that, when the genera are once cor- 
rectly determined, they may be pretty easily defined by the variations 
of these parts alone; but it has long since been seen how the con- 
