410 STRUCTURE AND CLASSIFICATION OF BIRDS 



hinge line separating the 

 cranium from the face. 

 This is present in Pele- 

 canus and Phaeton, while 

 in Phalacrocorax and 

 Plotus the existence of 

 fibro-cartilage allows of a 

 free motion. 



The lacrymal in Frr- 

 gata and Pelecanus is large, 

 with a large descending- 

 process, which in both 

 reaches the jugal bar ; in 

 addition Fregata has an 

 uncinate bone, which 

 reaches the palatine. Of 

 this there is apparently a 

 rudiment in Phaeton. 



In Phalacrocorax the 

 descending process of the 

 lacrymal completely blends 

 with the ectethmoid to 

 form a ring of bone, as in 

 the Limicolse. In Plotu* 

 the same thing occurs, but 

 the lacrymal is much 

 smaller. The interorbital 

 septum as an ossified 

 structure is almost com- 

 plete in Pelecanus and 

 Fregata, largely deficient 

 in Phaeton, almost absent 

 in Phalacrocorax and 

 J'lotitx. Iii Phalacrocorax 

 c<irl)o there is a small 

 bonelet resting upon the 

 jugal bar in front of the 



FIG. 191.- SKULL OF Fregata. VENTRAL l acryma l ; i this is also 

 ASPECT. (AFTER BEDDARD.) 



Vo, voiner : M.I-/J, maxillo-palatines : A', upwardly ' Ossicilltliii Sllprajurjalc of BRANDT. 

 directed part of maxillo-palatines. 



