1898.] or scxTHEOPS nov^i-holljlndi.!. 45 



§ External Characters and Pterylosis. 



This Cuckoo has a small nude oil-gland. There are 10 rectrices. 

 The fifth remex is not missing ; the bird is therefore quinto- 

 cubital. The pterylosis has, as already mentioned, been described 

 by Xitzsch ; and 1 have not much to add to his account. The 

 ventral tract, however, appears to me to bifurcate at the commence- 

 ment of the breast ; each half then, as in Centropus &c.\ again 

 divides into an inner and outer branch. I find these two branches 

 more distinct than they are figured by Nitzsch, while their point 

 of rejunctiou is beyond the posterior margin of the sternum and is 

 not very conspicuous. On the dorsal surface of the body the 

 median apterion is distinct but narrow ; there is no brealc between 

 the anterior and posterior portions of the dorsal tracts, such as 

 occurs in some Cuckoos. 



§ Muscular Anatomy. 



In dissecting the muscles of this bird the first poiut to which I 

 attended was the arrangement of the muscles of the thigh. Garrod" 

 divided the Cuculidse into two groups, one with the muscular 

 formula ABXY-f-, the other with the reduced formula AX 5^-1-. 

 Garrod's list was afterwards extended by myself ^ Seythrops 

 belongs (as I expected that it would, after an examination of the 

 pterylosis) to the former group. It has the complete muscle- 

 formula, both femoro-caudal and accessory femoro-caudal being 

 large and fleshy. They fuse early and are inserted in common. 



The ambiens is large and conspicuous. 



The glutcms primus extends beyond the acetabulum. 



There is one other poiut in the structure of the hind limb to 

 which I desire to direct attention. Garrod* described the deep 

 flexor tendons of the Cuculidae as " Galhnaceous," i. e. the tendon 

 of the flexor longus hallucis is united to the common tendon of 

 the flexor profundus by a vinculum. This statement has been 

 copied as applying generally to the Cuckoos. It does certainly 

 apply to a large number, including Scythrops. But the late W. A. 

 Torbes found that in C'entropus and Pyrrhocentor the flexor longus 

 hallucis is totally absent. 



As to the muscles of the fore limb I have nothing of interest to 

 record. The tensor patayii brevis tendon is simple and undivided ; 

 it is reinforced by no biceps slip. 



The expansor secundarioriim is present. The anconeus longus 

 sends off a tendinous slip to the humerus as in most Cuckoos. 



§ Visceral Anatomy. 

 On opening the body-cavity of Scythrops an arrangement of 



' Beddard, " On the Structural Characters and Classification of the Cuckoos," 

 p. Z. S. 1885, p. 16S. 



- " On certain Muscles of the Thigh of Birds, &c.," P. Z. S. 1873, p. 62«. 



^ Loc. cit. 



* " On the Disposition of the Deep Plantar Tendons in different Birds " 

 P. Z. S. 1875, p. 339. 



