542 Mr. R. Shelford 07i some 



Rliytidoceros undulatus. — Of this species I have two young 

 nestlings, oue slightly older thau the other; both are almost 

 identical in their external characters, and differ but little 

 from the nestling of B. rhinoceros just described. The 

 beak is deeper and more sinuous in outline than in B. rhino- 

 ceros ; a deposition of calcareous salts on the tip of the uppt r 

 mandible marks the shell-breaking junction of this part ; 

 the lower mandible is less abruptly truncated, and the small 

 papilla has disappeared in the older of the two specimens. 

 The rectrices and remiges are a trifle more advanced than in 

 B. rhinoceros; but the distribution of the feather-papillse 

 and their state of development is the same. 



Dimensions of Specimen No. 1. — Total length 155; upper 

 mandible 21 ; lower mandible 31 ; neck 33 ; antebrachium 

 19; manus 18; tibia 35; tarso-metatarsus 27 ; hallux 10; 

 3rd digit 9-5. 



Dimensions of Specimen No. 2. — Total length 165 ; upper 

 mandible 24; lower mandible 34; neck 35; antebrachium 

 24; manus 22 ; tibia 41; tarso-metatarsus 27 ; hallux 11; 

 3rd digit 9-5. 



Stage 4. — One six-weeks-old nestling of Buceros rhinoceros. 

 (PI. IX. figs. 1, 1 a, & 2.) 



I, unfortunately, have nothing intermediate between this 

 and Stage 3 ; but I have waited so long for material to fill 

 this gap that I quite despair of ultimate success. The head 

 is no longer conical in shape, the beak is much longer 

 proportionally to its depth, and the tongue is proportionally 

 smaller. The cloacal aperture is most remarkably pro- 

 minent, protruding very considerably beyond the general 

 contour cf the body. The pygidium is still turned forward 

 and consequently conceals the oil-gland. The skin is still 

 very loose and much wrinkled, but the feathers have pushed 

 their way out in certain areas, now to be described "^ : — 



Pteryla capitis covers the top, back, and sides of the 

 head, and runs for a short distance down the back of tlie 



* In Plates VIII., IX., & X. ouly those feathers which have actually 

 made their appearance are drawn ; the feather-papillae are disregarded. 



