208 ZOOLOGICAL RESEARCHES 



Buceros semifasciatus, 



Buceros semifasciatus ('Temm. in litt.), Hartl. J. f. 0. 

 1855, p. 356; kl. Orn. W. Afr. p. 103; — Schl. Mus. 

 P.-B., Buceros, p. 13. 



Buceros fasciatus , Rchw. J. f. Ü, 1875, p. 13, and 

 1877, p. 18. 



Tockus semifasciatus, Elliot, Mon. Buc. 1882. 



Halj. West Africa , fi-ora Seuegambia to the Gold Coast ; 

 Gaboon ? 



A large series , collected along tlie St. Paul's River and 

 at Grand Cape Mount, proves this species to be a well- 

 established one, although Dr. Reichenow (1. c.) believes 

 it to be but the not fully adult stage of B. fasciatus. 

 unfortunately I could uot obtain quite young specimens , 

 but a not full-grown one has the white to the 2°'l and 

 d^'^ pair of tail-feathers much smaller than fully adult ones 

 and intermixed with black spots, which peculiarity might 

 lead to the conclusion that in young birds these feathers 

 are entirely black, like Dr. Reichenow observed in young 

 specimens of his B. fasciatus. The strongest argument of 

 these feathers never becoming entirely white as is the 

 case in B. fasciatus , is given by a very old moulting male , 

 collected at Bavia. This specimen has the fully developed 

 Brd pair of tail-feathers tipped with white at the usual 

 length of 8 to 9 cm., and also is the 2"'^ pair, though 

 this latter is freshly moulted and but a little of the black 

 basal part developed. In these half-grown feathers the 

 white of the terminal part is arranged in the same way 

 as in fully developed ones , i. e. it reaches farther up to- 

 wards the base on the inner web than it does on the 

 outer one, and still farther along the shafts. These two 

 facts will thus lead to the conclusion , that in the first 

 plumage the white tips are gradually obtained by a mere 

 change of color, while moulted feathers have the white 

 tips at once at the usual length. Moreover among more 



r^otes from the Ley den ^luseum. Vol. VII. 



