2 Mr. W. P. Pycraft on the 



sloth will be considered to have been satisfactorily explained 

 away. 



For purposes of convenience it will be expedient to de- 

 scribe the pterylosis of the adult specimens first, commencing 

 with — 



1. Calodromas elegans. (Plates I., II.) 



PterylcB : — 



Pt. capitis (PI. I., Pt.cap.). — The plumage of the head 

 is produced forward on each side of the beak into a conical 

 process, terminating at the posterior angle of the external 

 nares. The two processes enclose between them a large 

 portion of the cere"^. The eyelids are provided with eye- 

 lashes. 



The feathers of the inter-ramal space are collected into a 

 distinct tract, with a relatively wide apterion on either 

 side ; at a point corresponding to the angle of the gape the 

 apterion ends abruptly, the plumage blending with that of 

 the side of the head and neck. 



Pt. spinalis (PI. II., Pt.s.). — Arising at the nape of the 

 neckj it divides soon afterwards into two long narrow 

 tracts enclosing a spacef. Coalescing between the humeral 

 tracts, they soon after again divide, and at the same time 

 increase greatly in width. Just in front of the thigh a branch 

 is sent down to the femoral tract, the main stems of the 

 tract retaining their independence for a short distance 

 further, and then fuse at a point roughly corresponding with 

 a line drawn across the back from the acetabulum. The 

 remainder of the tract is now continued backwards, finally 

 to blend with the pteryla caudse (PI. II. fig. 1). 



Pt. caudalis (PI. IL, Pt.c). — The rectrices are but 

 little longer or stronger than their coverts, and not easily 

 distinguished. They are 10 in number. 



Pt. colli lateralis {VI. I., PI. II., Pt.col.lat.).— The 

 lateral cervical tract, at its upper end, fuses in the mid- 

 ventral line with that of the opposite side, whilst the dorsal 



* See Rhamphotheca, p. 8. 

 t See Apt. spinalis, p. .5. 



