474 



MR. W. A. FORBES ON LEPTOSOMA DISCOLOR. [June 15, 



a small notch ; behind they are less and les^ complete as they go 

 downwards. The first semirings are posteriorly closely applied 

 to, though separate from, the pessulus, and are apparently continued 

 on, as cartilaginous rings, posteriorly, so as to form complete or 

 nearly rings. The posterior ends of the second and third semirings 

 where they appear behind are widely separated from their fellows of 

 the other side. The fourth and succeeding bronchial rings are all 

 cartilaginous. Of these the fourth is the largest, being nearly straight, 

 and slightly more prominent than the others. To its middle, rather 

 towards its posterior margin, is attached the (single) intrinsic syrin- 

 geal muscle. The rings succeeding the fourth ring rapidly become 

 more and more complete, at the same time that the bronchus be- 

 comes less capacious, the whole tube tapering away from this ring 

 as it approaches the lung. The fifth and sixth semirings are more 

 slender than those that succeed them, and are slightly concave up- 

 wards. The remaining ones are straighter and deeper. Except be- 

 tween the fourth and fifth, and fifth and sixth semirings, the inter- 

 annular intervals are exceedingly narrow. 



This syrinx does not show much similarity of form to that of 

 Co7-acias garrula, the only one of the family of Coraciidie that I have 

 been able to examine as regards this point. At the same time it 

 does not much resemble that of any Cuckoo I am acquainted with. 



Reviewing the facts already stated, it is clear that the affinities of 

 Leptosoma to the Cnculidse are very remote, whilst, on the contrary, 

 its relations to the Coraciidse are quite the reverse. The subjoined 

 tabular statement of the principal points in the structure of the three 

 just named groups will perhaps render this additionally clear : — 



In common with both Cuculidae and Coraciidse, Leptosoma pos- 

 sesses a nude oil-gland and long caeca, two carotids, and the femoro- 

 caudal, semitendinosus, and accessory semitendinosus muscles. Wher- 

 ever there is any difference, Leptosoma resembles the Coraciidae ; 

 and the same story is told by the pterylosis and tensor-patagii 



arrangement. 



Nevertheless, both in the syrinx and in these last two points, as 

 well as in some others, especially osteological ones\ Leptosoma is 

 not quite typically Coraciine, and it may therefore be retained, as 



' Vide Grandidier's work, Atlas, Ois. pis. 85, 86. 



