428 



STRUCTURE AND CLASSIFICATION OF BIRDS 



there is the ordinary vinculum and a special slip to 

 digit II. 



The lungs in the Ciconiidae are at least often distinguish- 

 able from those of the Ardeidae by the great deficiency of the 

 muscles arising from the ribs and attached to the pulmonary 

 aponeurosis. In Cancroma there were four pairs of such 

 muscles, arising from a corresponding number of ribs, in 

 Nycticorax five ; but in Ciconia alia I only found one 

 pair inserted on to the aponeurosis in front of the septum 

 bounding the anterior intermediate air sac anteriorly. Pro- 

 fessor WELDON found no such muscles in a considerable 

 number of storks. 



The tongue is always small. The proventriculus is 

 zonary. The liver is nearly equilobed, and there is always 

 a gall bladder. The intestinal measurements of a number of 

 species are as follows : 



The number of cervical vertebra? is seventeen (Lcpto- 

 ptilus, Tanliilux) or eighteen (Xenorhynchus) ; the hypapo- 

 physes are feeble ; there is a ventral canal formed by 

 union of catapophyses of C7-C11 (Xenorhynchus), C7-C12 

 (Tantalus}. Four ribs reach the sternum in Xenorhynchus, 

 five in the others. The sternum has one pair of notches, and 

 the spina externa is absent or small. The procoracoid is of 

 fair size, but does not reach the clavicle ; the coracoids meet 



