468 DR. R. W. SHUFELDT ON [Nov. 16, 
At the present time, the American Ornithologists’ Union place the 
Cuckoos of this country in an order Coceyges, having three sub- 
orders, the Cuculi, the Trogones, and the Aleyones, our genus 
Geococcyx falling into the first under the subfamily Coccygine, there 
being one other associated with it, the genus Coccyzus. : 
Not long ago I showed some of the peculiarities of the coloration 
and extent of the naked skin-tracts upon the head of this bird’; I 
regret to say, however, that I have not at hand an account of the 
pterylosis of the Cuculidz, so on the present occasion I must content 
myself with an accurate description of that feature in Geococcyx 
californianus, and leave the comparisons to be made by others who 
may be more fortunate in this respect. 
Of the Pterylosis of Geecoccyx. 
So carefully have I drawn the two views of our subject, which are 
presented in Plate XLII., showing the pterylee and their exact limits 
and extent, that a few words will suffice to complete the description. 
It will be seen that the “capital area” is quite complete, being 
broken only by the naked and coloured skin-tracts about the eye 
and on the back of the head. These latter vermilion-tinted skin 
areas are divided in the median line behind by a very narrow pteryla, 
which is directly continuous with the posterior middle strip of an 
equal width, and which terminates at the root of the neck, where it 
is somewhat abruptly lost in a central, sparsely scattered tract, just 
anterior to the spinal pterylosis. This posterior cervical strip is 
continuous above with the capital area. Upon the anterior cervical 
region we find the tract quite broad above, where it is continuous with 
the feather-tracts of the gular space; but as we proceed down the 
front of the neck this tract bifurcates at about halfway between the 
trunk and the throat, each separate strip thus formed being extended 
on either side to a point opposite a clavicular head, where it merges 
into the “ ventral” and ‘‘ humeral tracts.” 
A “ humeral tract ” is but faintly marked in our Ground-Cuckoo ; 
and it is seen to pass, on the posterior aspect of the brachium, from 
the shoulder toward the elbow, but is gradually lost before it arrives 
at the latter point (Plate XLII. fig. 1). 
The “ventral tracts ’’ are very broad anteriorly, and are bounded 
mesially by curved lines, which overlie the clavicular limbs. These 
tracts, on either side, also bifureate as we proceed in the direction of 
the abdomen. The outer strip grows gradually narrower, and makes 
a graceful curve round under the arm-pit, below which it abruptly 
terminates. The mesial strip formed by the bifurcation of the 
ventral tract is long and narrow, being gently convex outwards for 
its entire length. The distal extremities of these strips become 
extremely slender as they converge towards the vent, around which 
they pass to merge with each other behind this. opening, and with 
the feather-tract covering the underside of the coccygeal protu- 
berance (Plate XLII. fig. 2). 
1 This, 1885, pp. 286-288, pl. vii. 
