PALAEOCHENOIDES MIOCEANUS 557 



dyles project farther on the ventral surface, and the distal end of 

 the femur is greatly expanded at the condyles, the shaft being 

 slender in comparison. In the Steganopodes (save in the Phalacro- 

 coracidae) the condyles are less produced ventrally and there is a 

 gradual broadening of the shaft until it merges gradually into the 

 condyles. In the Anseriformes, in general, the lateral diameter 

 of the shaft of the femur where the expansion for condylar support 

 ceases is less than one-half the greatest lateral width through the 

 condyles (the measurement of the shaft in this case not being abso- 

 lutely its smallest diameter, but usually the breadth at a point 

 one-third of the length of the femur from its distal extremity). 

 In the Sulidae, the brown pelicans, and the snake-birds this diam- 

 eter is more than one-half of the condylar width. Some cormorants 

 have it greater (P. albiventris) , and some less. In all of these points 

 Palaeochenoides resembles the totipalmate birds, and it is referred 

 without question to the Steganopodes. The distal end of the 

 femur representing Palaeochenoides, while similar to that of our 

 present-day pelicans, differs in having a posterior pneumatic 

 foramen, the popliteal space divided by a rounded elongate ridge 

 (extending at an angle posteriorly from the pneumatic fossa), 

 the outer condyle broader and stronger, and the intercondylar 

 channel deeper and more narrow, with no depression evident on the 

 dorsal face of the shaft immediately posterior to the origin of the 

 condylar ridges. Should more of the skeleton become known, it 

 may eventually be placed in a separate family. If we may venture 

 to base theory upon this one fragment, Palaeochenoides was a 

 pelican-like bird somewhat larger than Pelecanus erythrorhynchos 

 or P. onocrotalus, as the portion of the femur representing it seems 

 to indicate that the bone in its entirety was somewhat larger and 

 heavier than the femur in these two species. In its appearance 

 this bone seems, too, to show certain resemblances to the Sulidae 

 and remotely to the Anhingidae and the Phalacrocoracidae. 

 Hence, while Palaeochenoides will stand as a milepost in the line of 

 descent of the pelicans, it brings down to us suggestions of general- 

 ized development indicating ancient relationships of pelicans to 

 gannets and more remotely to the cormorant-anhinga branch of 

 the totipalmates. 



