432 



STRUCTURE AND CLASSIFICATION OF BIRDS 



are very straight bones, usually cut very squarely behind, 

 but notched postero-laterally in Ardea bubulcus, A. mhtnta, 

 A. coniata, with well-marked internal laminae, which extend 

 quite to the posterior end of the bone. The interorbital 

 septum is largely fenestrate. The bony ectethmoids are but 



little developed ; Cancroma is in 

 several ways rather anomalous. It 

 is heron-like in the fenestrated in- 

 terorbital septum, and in the fact 

 that the internal lamina of each 

 palatine is continuous to the posterior 

 end of that bone. The nostrils are 

 continued forward by a deeper groove 

 than that which is formed in the more 

 normal herons a point of likeness 

 this to Scopus and Balceniceps (qq.v.) 

 The very broad palatines join the 

 vomer again in front of their posterior 

 junction with each other, thus divid- 

 ing the interpalatine vacuity into two 

 areas. It is thus to a certain degree 

 ' doubly desmognathous,' and is so 

 far like Xenorhynchus (see p. 429). 

 There is a well-marked lateral process 

 of the palatines, as in Scopus and 

 storks. 



As in Scopus the procoracoid 

 is very small and the coracoids overlap 

 each other at their insertion. Like 

 the storks, and unlike Scopus, the 

 hypocleidium articulates with the end 

 of the carina stermV The hypocleidium, moreover, projects 

 backwards between the two clavicles as a narrowish piece. 



The hflemapophyses of the cervical and dorsal vertebra 

 are small, those of the latter being sometimes quite absent. 

 There is a catapophysial canal (in Cancroma as well as 

 .Irdca), formed in the two types mentioned by cervical 

 vertebrae 7-12. 



FK;. '202. VENTRAL SUR- 

 FACE OF SKULL OF Ardea 

 ciii/'n'd (AFTER HUXLEY). 



J't, pterygoids ; /'/, palatines ; )', 

 vomer : Jf.rj>, maxillo-palatines. 



