BIRDS. 173 



Pigeons : the grooves themselves do not quite meet. The keel is very large, and complete to the 

 end ; it has a deeply concave front margin, for the angle sends a considerable hooked process for- 

 wards, to articulate with the furcula. In Leptosoma discolor (op. cit., p. 687, figs. C and 7) 

 the scapula is ensiform, with a very long sharp point, as in Cuculus ; but the coracoid is very 

 different, for the meso-coracoid plate runs down the inner edge of the shaft, as in Corythaix, and 

 to a less degree than in Coracias. The furcula also agrees with both of those Birds rather than with 

 the true Cuckoo ; as in Coracias it is U-shaped, and the inter-clavicle is scarcely distinguishable ; 

 from Corythaix it differs in the rami being confluent, but agrees closely with that type in the 

 thickened shoulder formed by the "pre-coracoid segment." This is seen in a less degree in 

 Coracias and Cuculus. The Sternum is intermediate in form between that of Cuculus and 

 Corythaix, being wider behind than in the latter, and narrower than in the former. Here the 

 outer xiphoid bar has a small triangular notch converting it into two diverging bars, and the 

 inner process is narrow. The costal processes are not squared, as in Cuculus, but rounded, 

 as in Corythaix and Coracias ; the rostrum is inferior, similar to that of Coracias, but smaller, 

 and the keel, as large as that of the Cuckoo, has a more convex front margin, and a much 

 less projecting angle, to which the furcula is attached by a much longer ligament. 



Family" BUCERIN^E." 

 i 



Examples. Buceros albirostris, Shaw ; B. ruficollis, Vieill. 



My skeletons of Hornbills (the gift of Dr. Sclater) are those of Buceros albirostris and B. ruf,- 

 cQllis. The scapula is ensiform and very straight, especially in B. albirostris, and the acromion is 

 thick and square-ended ; the coracoid is stouter than in Hampliastos, and its meso-coracoid process 

 is well developed, but free, and not decurrent : the epicoracoid region is expanded and slightly 

 hooked. The furcula forms a very wide U, but the halves are not united in B. albirostris ; they 

 become very slender below, but above they are very thickly clubbed and cellular ; this is due to 

 the large size of the " meso-scapular segment," for the prse-coracoid segment is but little deve- 

 loped. The Sternum agrees with that of the Cuckoo (Cuculus} in the single pair of rather small 

 notches, in the bilobate middle xiphoid plate, and in the degree in which the xiphoid region 

 expands laterally. But in these two species the outer xiphoids project beyond the middle part, 

 instead of being shorter; they are shorter, however, in B. violaceus (Hunteriari Mus., Nos. 1486 

 and 1487) : in all the xiphoid ends are permanently soft. The rather shallow keel projects forwards 

 as in Picus, Psittacus, and Ramphastos ; but it forms a more acute angle. The costal processes, 

 are obliquely quadrangular, and there are four pairs of condyles in B. ruficollis, but only three in 

 B. albirostris, a state of things to be seen also in Tinamus robustus, Botaurus stellaris, and Tigri- 

 soma leucolophum ; but it is rare in the Bird-class. The rostrum is more differentiated 

 from the front of 'the keel than in the higher Pici ; it is inferior in B. rufaollis, and it has a 

 rudimentary superior rostral process, as in Cuculus ; but it ascends between the coracoid grooves 

 (very distinct in both), in B. albirostris. In the latter species we have a very beautiful morpho- 

 logical character, namely, a "fenestra," tending to cleave the "rostrum" off from the rest of the 

 ento-sternum ; a character better developed in Upupa (see Plate XIII, fig. 15), and very constant 

 in most of the Galling. 



