NO. II CLASSIFICATION, BIRDS OF THE WORLD — WETMORE 9 



possibly may be subject to other interpretation. It is desirable now to 

 place the Odontopteryges at the beginning of the order because of their 

 antiquity. The known history of the group, which begins in the early 

 Eocene, indicates probable ancestry in Paleocene time. The pointed 

 projections on the jaws, assumed to have been sheathed in the in- 

 tegument of the bill, were without question used in seizing prey. The 

 disappearance during Miocene time of such a holding apparatus may 

 indicate that the bony projections were not completely successful for 

 their purpose, perhaps because of their hollow centers, as accidental 

 breakage in them would not be restored. The fine serrations restricted 

 entirely to the ramphotheca, found in the straight-billed species of the 

 pelecaniform order (tropicbirds, gannets, boobies, and anhingas), 

 may be regarded as a functional replacement. 



The change in position made to the beginning of the order covers 

 only the Odontopterygidae and the Pseudodontornithidae and leaves 

 Cladornis and Cruschedida still unsettled as to relationship. As ex- 

 plained above (p. 4), Ameghino described both as forms of penguins, 

 but Simpson says that they have no connection with this group. As the 

 suborder Cladornithes, they are located in their former uncertain 

 position at the end of the Pelecani formes. 



Suborder Ardeae. — The general resemblance of the boat-billed 

 heron (Cochlearius cochlearhis) to the night herons has been the 

 occasion of differences in allocation of its rank in classification from 

 that of a subgenus of Nycticorax to full family status. In a recent 

 review of the Ardeidae, Bock (1956, pp. 31-35) has treated it as a 

 separate genus in a "Tribe Nycticoracini" allied to Nycticorax. Super- 

 ficially the boatbill is like a black-crowned night heron, but in detail 

 there are outstanding differences. The enlarged bill is obvious, and 

 there are four pairs of powder-down patches, instead of the three 

 found in the other herons. In the skull, the bill has been changed 

 from the spear point usual in herons to a broad scoop with the roof 

 of the mouth smoothly arched. The lower jaw is widely bowed to 

 fit this change, and the symphysis is greatly reduced in length. The 

 palatines are so greatly broadened, and so inflated on the outer 

 posterior margin, that they have little resemblance to the ordinary 

 heron form. The quadrate has the orbital process shorter and thicker 

 and the mandibular articulation narrowed ; the lachrymal is small ; the 

 eye opening considerably enlarged to house the exceptionally large 

 eye ; and the external nasal opening considerably reduced. The palatal 

 musculature is decidedly stronger than in the true herons. 



In life boatbills act like night herons, as they roost and nest in 

 groups and are mainly nocturnal. When hunting at night, I have 



