Hornbill Embryos and Nestlings. 543 



neck. The skin between the rami of the mandibles is devoid 

 of featliers, save for a few bordering bristles. The eyelids are 

 provided with eyelashes, those of the upper lid being the 

 more strongly developed ; they have the same structure 

 as the rictal bristles {cf. PI. IX. fig. 1 a), but are singly 

 disposed^ not arranged in groups. These filoplumes are 

 either fine single bristles, or double, or else terminate in a 

 somewhat trident-like fashion. 



Pt. colli. — OP this future well-developed and solid tract 

 very little can yet be seen, neither the pt. spinalis nor the 

 pt. ventralis having absolutely established their conuection 

 with the pt. capitis. Ventrally a few minute tips can be seen 

 on the lower part of the neck ; laterally not even feather- 

 papillse can be distinguished. 



Pt. spinalis .—The feathers forming this tract are not far 

 advanced, none being actually visible above the middle of 

 the back. The tract quickly broadens out, then narrows 

 again, and finally spreads over the pygidium to fuse with 

 the coverts of the rectrices. A short narrow branch is sent 

 up on each side towards the jjt. femoralis, from near the 

 termination of the p/. spinalis. 



Pt. ventralis commences at the base of the neck ; its 

 connection with the pt. colli is, however, not yet established. 

 Almost immediately the tract forks, the branches running 

 down as far as the lower edge of the sternum. The lower 

 feathers are white. I will here just notice a short tract 

 which runs from the proximal third of the humerus, down- 

 ward towards the pt. ventralis. I shall have more to say 

 concerning this later on. 



Pt. humeralis. — Continuous with the pt. alaris. 



Pt. ani. — A ring of feathers surrounding the prominent 

 anus. 



Pt. femoralis. — A few, but well-developed, feathers running 

 into a strong Pt. cruralis, the feathers of which are white. 



Pt. uropijgii. — The oil-gland is densely tufted. 



Pt. alaris.— (PI. IX. fig. 2.) 



Metacarpo- digitals. — The tips of tlie 2nd to the 11th have 

 appeared, as is the case with the cubitals ; the tip of the 1st 



