432 STRUCTURE AND CLASSIFICATION OF BIRDS 



are very straight bones, usually cut very squarely behind, 

 but notched pqstero-laterally in Ardea bubulcus, A. minuta, 

 A. comata, 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 ; Gancroma 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 storlis, and unlike Scopus, the 

 hypocleidium articulates with the end 

 The hypocleidium, moreover, projects 

 backwards between the two clavicles as a narrowish piece. 



The hsemapophyses of the cervical and dorsal vertehrm 

 are small, those of the latter being sometimes quite absentk 

 There is a catapophysial canal (in Gancroma as well as 

 Ardea), formed in the two types mentioned by cervical 

 vertebrae 7-12. 



Pig. 202.— Ventral Sck- 

 FACE OF Skull of Ardea 

 cinerea (aftek Huxley). 



Pt, pterygoids ; JH, palatines ; Vo, 

 vomer ; Mxp, masillo-palatines. 



of the carina sterni. 



