289 



1515. The skull of the common Hoopoe (Up*pa epopt). Hwntena* 



1516. The skull of the common Hoopoe (Uptipa rpopt). 



Pretfnted by William Home Cliff, K*q. 



Tribe HKTKRODACTYU. 



Genus Cyjaeltut. 



1517. The skeleton of the Swift (Cyp*eln Aptu). 



Of the 16 vertebrae between the ikull and sacrum, the five posterior bear moveable rib*, 

 the but four pain of which unite with the sternum : there are two pun of sacral rib*. The 

 sternum is entire and long, but dor* not extend to far back ai in the Humming-bird*. Tin 

 depth of the keel exceeds the greatest breadth of the sternum. The arch of the furculura is 

 wide and rounded. The scapula is narrow, but of great length, almost reaching to the ilium. 

 The humerus is very short and thick, with strong pectoral and deltoid processes, and with a 

 trochlear groove on the back of the outer condyle. The ulna is more than twice as thick as 

 the radius ; both are short and straight. The metacarpus surpasses them in length, and tin- 

 proximal phalanx of the middle digit is unusually broad and deeply excavated on its outer 

 xurface, for the attachment of the bases of the long primaries, or quill-feathers of flight. Not 

 any of the four toes are directed backward*, and the outer or fourth toe, with the third as 

 well as the second, hare but three phalanges. 



The chief modifications in the skeleton of this bird relate to it* wonderful powers of flight ; 

 the shortncM of the metatarsus and the position of the toes, to it* habit of clinging to and 

 climbing vertical surfaces, and to its defective powers of perching. 



.!/*. South. 



1518. The skull of the Swift (Cypgefa Aptu). Purcktued. 



Genus Trockiltu. 



1519. The skeleton of a Humming-bird (Trockil** Clemfnciai). 



The occipital region is indented by two vertical channel*, which converge as they ascend, 

 bounding laterally the cerebellar prominence and meeting upon the upper median depression, 

 between the cerebral prominence* : the long cornua of the hyoid play in these channel*. 

 The lacrymals are large, and form the anterior boundaries of the capacious orbit*. 



The chief peculiarity in the skeleton of the birds of this family is the great extent of the 

 sternum, which reaches backwards to below the last caudal vertebra, and the enormous depth 

 of the keel, which surpasses that of the entire thorax. The humeru* i* short, but character- 



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