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Show 468 DR. R. W. SHUFELDT ON [N' At the present time, the American Ornithologists' Union place the Cuckoos of this country in an order Coccyges, having three suborders, the Cuculi, the Trogones, and the Alcyones, our genus Geococcyx falling into the first under the subfamily Coccygma?, 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 Cuculidae, so on the present occasion I must content myself with an accurate description of that feature in Geococcyx calif or nianus, and leave the comparisons to be made by others who may be more fortunate in this respect. Of the Pterylosis of Geococcyx. So carefully have I drawn the two views of our subject, which are presented in Plate XLIL, showing the pterylae 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 fiather-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 bifurcate 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 opeuing, and with the feather-tract covering the underside of the coccygeal protuberance (Plate XLII. fig. 2). 1 Ibis, 1885, pp. 286-288, pi. vii. |