1885.] MR. F. E. BEDDARD ON THE CUCKOOS. 179 



inferior tract again divides, and each half is continued on either side 

 of the sternal carina, narrowing gradually, until the termination, a 

 little way in front of the cloaca ; on either side a branch two 

 feathers wide is given off to the humeral tract and another of the 

 same width to the row of feathers which occupies the anterior portion 

 of the patagium ; the inferior tract of either side has no outer 

 branch ; and the disposition of the whole tract is therefore similar to 

 that of Cuculus and Piaya, more especially the latter. The spinal 

 tract is narrow and very closely feathered upon the neck ; it 

 bifurcates into two narrow, also closely feathered tracts at the 

 junction of the neck with the body ; the rest of the spinal tract 

 is separated by a distinct break from the anterior portion, and 

 considerably wider, and at the same time less closely feathered upon 

 the lumbar region, where it is continuous with the femoral tract j 

 on a level with the articulation of the femora the two halves of the 

 spinal tract reunite and run as far back as the base of the oil-gland 

 as a single closely-feathered tract. 



Diplopterus ncevius. — I have only been able to examine one 

 example of this Cuckoo, but, so far as I could make out from that 

 example, the pterylosis agrees fairly closely with that of the 

 Cuculine forms, as it might be expected to do from the structure of 

 the syrinx ; I do not, however, feel able to speak at all positively 

 upon the subject. 



Geococcyx. — Of this genus I have been able to examine Geococcyx 

 affinis, and another species not named ; it does not present any 

 differences from G. affinis. 



The ventral tract commences from the point of junction of the two 

 rami of the lower jaw, and at first only occupies the extreme middle 

 of the area of stem uniting the mandibles ; further back it becomes 

 wider ; on the neck the feathers have the characteristic arrangement 

 already referred to under the description of Centropus. The ventral 

 tract, after giving off a single row of feathers to the hyposternum, 

 divides as usual : the inner broader limb is two feathers wide, the 

 outer is a single row of feathers ; they do not reunite posteriorly. 



The spinal tract increases in strength, but decreases in width, 

 towards the junction of the neck with the trunk ; as in other species 

 (e. g. Centropus) there is a complete, or an almost complete, break 

 between the cervical portion of the spinal tract and its two posterior 

 halves ; furthermore the anterior portion of the tract does not 

 bifurcate posteriorly, but ends abruptly between the shoulder-blades, 

 being at this point two feathers wide. The spinal tract is not connected 

 with the humeral tract, there is a completely nude space between them. 

 The two halves of the posterior section of the spinal tract are 

 separated by a considerable break from the cervical section ; at first 

 each is formed of a very few scattered feathers, but the feathering 

 soon gets stronger ; at about the level of the attachment of the 

 femora the two halves of the spinal tract unite. 



The femoral tract is very distinct in this Cuckoo, more so than in 

 any species which I have examined : instead of a diffuse feathering 

 over the whole upper surface of the thigh, the feathers are mainly 



12* 



