94 COPE 



tendons, where the first and second form a common stem, 

 and the third and fourth a common stem, following the ar- 

 rangement of the digits. (Fig. 32). 



Tlie palatal structure must be consulted in attempting 

 the discrimination of the orders of birds. There are four 

 types of structure, as follows : First, the dromfeognathous 

 palate (Fig. 33 D) has the anterior roof continuous and 

 formed of the fused maxillopalatines and vomer. In this 

 case, also, the vomer and pterygoid bones exclude the 

 palatine from contact with the presphenoid, by intervening 

 between the two. In the desmognathous palate (Fig. 33 C) 

 the maxillopalatines join each other on the middle line, 

 excluding the vomer, which is free and above them or 

 aborted. Both palatines and pterygoids reach the pre- 

 sphenoid bone at its basipterygoid processes. In the schiz- 

 ognathous palate (Fig. 33 B) the maxillopalatines do not 

 meet on the middle line, and the vomer terminates in a free 

 acute apex above, and more or less posterior to them. The 

 fourth type (the segithognathous, Fig. 33 A) is a modifica- 

 tion of the schizognathous, differing only in the form of the 

 vomer. The anterior extremity of the latter is flattened, 

 often expanding and notched or excavated on the anterior 

 margin. 



The families of the Euornithes are as follows : 



Steganopodes ; Phffitonidse, Fregatidse, Pelecanidae, Sulidse, 



Phalacrocoracidse, Plotidse. 

 Colioidei ; Coliidse. 



Chenomorphie ; Palamedeidae, Anatidee, Phoenicopteridffi. 

 Herodii ; Ibididee, Ciconiidse, Balsenicipitidse, Ardeidee. 

 Accipitres ; Cathartidse, Falconidse, Pandionidse, Strigidfe. 

 Heterospondyli ; Steatornithidse. 

 Coccygomorphas ; Cuculidse, Coraciidaj, Alcedinidse, Upupi- 



dte, Musophagidse, Todidee, Momotidas, Bucerotidse, 



