456 



ZOOLOG-ICAL EESULTS OE THE EUWENZOEI EXPEDITION. 



The Rhamphotheca. — There is the faintest perceptible trace of a notch at the tip 

 of the beak, and the nostrils are somewhat pear-shaped in outline, tapering forwards. 

 They are protected by a membranous operculum having a thickened free edge, and 

 the aperture posteriorly exposes a portion of a turbinal scroll. 



Rictal Iristles are barely traceable ; the aperture of the ear is large and opens 

 upwards and forwards. 



Pterylosis of Bradypterus compared with allied Forms. 

 Unfortunately it has been found impossible to institute a series of comparisons 

 between the pterylosis of Bradypterus and any considerable number of allied forms. 

 An attempt has been made, howevei-, towards this much desired end by contrasting 

 Bradypterus with one or two genera which are at any rate distantly allied. 



Text-fig. 15. 



''■ r 2 5 . 



The extended wing of Bradypterus, showing its rounded character. 



Bradypterus dd^ei's, irom. Sylvia and Phylloscopus in the shape of the dorsal expansion 

 of the pi!, spinalis, A\hich is fan-shaped and of considerable width, and this constitutes 

 a striking difference, since in the genera just referred to this region of the tract takes 

 the form of a long oval. Bradypterus differs even more from Acrocephalus, for in the 

 latter this expansion is of a A-shape, the stem and arms being very broad ; they join 

 two similar but very slender arms, which rapidly converge and form a narrow stem, 

 continued backwards to the uropygium. Thus a small more or less diamond-shaped 

 apterium is formed immediately over the pre-acetabular region of the ilium. 



Acrocephalus, Sylvia, and Phylloscopus all agree, however, in having rictal bristles, 

 and these are barely traceable in Bradypterus. Bradypterus, again, is peculiar among 

 these genera on account of the great length of the 10th primary. 



Acrocephalus, on the other hand, is peculiar in the specialized character of its feet, 

 since the toes and claws are conspicuously long, while the plantar surface of the toes 



