SHUFELDT : OSTEOLOGY OF THE STEGANOPODES . 185 



is comparatively as in carbo, but from this point the ramus tapers rapidly either way 

 so that, as a whole, the mandible is much weaker than that of carbo. 



"So too with the humerus, where the greatest proximal width is only 2 mm. 

 greater than in carbo, although the bone in its entirety is much more stoutly built." 



In a following volume of the Proceedings of the U. S. National Museum, in 

 which Mr. Lucas described the above specimens of bones of P. perspicillatus, he 

 on subsequent pages also described the skull of this species, and presented other 

 data of importance having reference to the Phalacrocoraddss (Vol. XVIII. , pp. 717- 

 719, Pis. XXXIV.-XXXV.). 



This second lot of bones were likewise obtained by Dr. Stejneger at Bering 

 Island in 1895, or thirteen years after the first specimens were collected by him. 

 A cranium and a sternum of P. perspicillatus are found in this second installment, 

 and they are very important discoveries. 



The cranium is now in the collection of the Museum (No. 19417, U. S. N. M.). 

 "In its general contour," says Mr. Lucas in his paper referred to above, "it most 

 closely resembles that of P. penicillatus among existing cormorants, but is decidedly 

 larger, and is proportionately wider than in that species, while the beak is shorter. 

 As far as mere size is concerned, the skull of an adult male of P. carbo would be as 

 long as that of P. perspicillatus, but the latter is much wider and is more depressed. 

 The cranium is readily distinguished from that of P. urile by its greater size and less 

 depression, and by having a proportionately stouter beak, whose ridge lacks the 

 slight but characteristic emargination found near the base of the beak in P. urile. 



"As a matter of fact, the differentiation of cormorants into species with grooved 

 beaks and those without does not exist, so far as the bony beak is concerned. Some 

 have deeper grooves than others, but all have more or less of a furrow along the side 

 of the mandible, and there is every degree of gradation, from such well-furrowed 

 beaks as those of P. albiventris and P. magellanicus to the shallow grooves of P. melan- 

 oleucus and P. carbo. 



" Pallas's Cormorant shows a marked difference from all others examined in the 

 development of the lateral ethmoid. In other species the lachrymal sends a process 

 inward which fuses with a spur from the mesethmoid to form a more or less L-shaped 

 bar of bone, uniting the frontal and mesethmoid. A small spur, arising from the 

 inferior inner angle thus formed, represents the lateral ethmoid, and this is' usually 

 but little developed, being largest in P. penicillatus and obsolete in P. urile. In P. 

 perspicillatus there is a lateral ethmoid plate, complete save for an opening above, 

 being the retention by ossification of a cartilaginous plate found in the nestling of 

 P. urile before the nostrils have become closed. The maxillopalatines are also 



