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 Coccyges, having three sub- 

 orders, the Cuculi, the Trogones, and the Alcijones, our genus 

 Oeococcijx falling into the first under the snbfamily Coccyginse, there 

 being one other associated with it, the genus Coccyzus. 



Not long ago I showed some of the pecuUarities 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 ihe CucuUd^, so on the present occasion I must content 

 myself with an accurate description of that feature in Geococcyx 

 calif ornianus, and leave the comparisons to be made by others who 

 may be more fortunate in this respect. 



Of the Ptetylosis of Geococcyx. 



So carefully have I drawn the two views of our subject, which are 

 presented in Plate XLII., showing the pterylse 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 verynarrow pteryla, 

 which is directly continuous with the posterior middle strip of an 

 equal width, and which terniinates at the root of the neck, where it 

 is somewhat abruptly lost in a central, sparsely scattered tract, just 

 anterior to the spinal pteiylosis. 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 fVather-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 tlie 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 eitlier 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 arni-|iit, 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 leather-tract covering the underside of the coccygeal protu- 

 berance (Plate XLII. fig. 2). 



1 Ibis, 1885, pp. 286-288, pi. vii. 



