VO i88ft n '] PROCEEDINGS OF THE NATIONAL MUSEUM. 89 



posteriorly wider, conforming in pattern very nearly to those of urile, 

 while dilophus resembles carbo in this respect. 



The trans-palatine angle is more rounded than in carbo, much more 

 than in urile, resembling in this dilophus. 



The inner portion of the post-palatine is less produced ventrally than 

 in carbo, and the pterygoid articulation wider and flatter than in carbo, 

 the palatine thus lacking the keel present in carbo. 



The same differences are found between the same parts of urile and 

 dilophus. 



The maxillo-jngal bar is as long as that of carbo but more slender. 



The lower mandible is slightly shorter and decidedly weaker than 

 that of carbo, and the lower mandible of urile is proportionately still 

 weaker than that of dilophus. 



The dentary portion of the mandible is more deeply grooved along 

 the inner surface than that of carbo, being comparatively the same as 

 in urile. 



The cutting edges of the mandible are comparatively straight as in 

 carbo and dilophus, but urile differs from all three in having the mandi- 

 ble distinctly recurved. 



The sternum is transversely flatter than that of carbo, being a trifle 

 more flattened even than that of urile. The carina is also shorter than 

 in urile, but in size and general appearance the sterna of perspicillatus 

 and urile resemble one another very closely. 



From manubrium to ineso-xiphoid the sternum is 13 min shorter than 

 that of carbo, being exactly as long as that of urile. 



The proportion of carina to total length is shorter than iu either carbo 

 or urile, the sternum from anterior end of carina to meso-xiphoid meas 

 uriug 2 ,nm less than that of carbo and 4 mm less than that of urile. 



Between the costal borders the sternum is slightly wider than in 

 either carbo or urile. 



The rudimentary manubrium, like that of urile, lies in the plane of 

 the body of the sternum, while in carbo and dilophus the manubrium 

 lies in the plane of. the keel. 



If a line be drawn between the costal processes it will be found that 

 thecoracoid articulatious project less beyond this line and form a more 

 obtuse angle with one another than they do in carbo, and the same is 

 true of urile as compared with dilophus. The sternum is non-pneumatic, 

 as in urile, but iu carbo and dilophus good-sized foramina pierce its 

 dorsal face just back of the ridge formed by the coracoidal groove. 



It is certainly interesting to find the sterna of these two represent- 

 atives of the sub-genera Phalacrocorax and Urile, respectively, agree- 

 ing with one another in these slight structural poiuts. 



Articulations are present for five pairs of ribs, the same number 

 as in carbo. One specimen of urile has four pairs of articulations, 

 another has five on the left side and four on the right, and dilophus has 

 but four pairs of costal facets. 



