Vol. XV. -j Shufhldt, Osteology of Harris's Cormorant. 8q 



inidillc placf Ix'twecii tiieiii, tlioiigh evidently very near the liist- 

 nanied groui) generally, if separated from it at all. In fact, a skull 

 of P. penicillatus (No. 940, Coll. U.S. Nat. Mus.) agrees very 

 closely in all of its essential characters with the skull of Nannop- 

 Icnim harrisi — at least, with the one l)elonging to the collections 

 of the U.S. National Museum numbered 19,628 ; and, character 

 for character, this agreement is nearer than it is in the case of 

 the aforesaid skull of Nannopterum harrisi and that of Phalacrocorax 

 carbo (No. 18,851, Coll. U.S. Nat. Mus.) Dr. Gadow claims, in 

 his article in the Novitales Zoologicce, that P. carbo is the " nearest 

 ally " of Nannoplcritm harrisi (p. 1O9). I must believe that he 

 did not have before him at the time a skeleton of P. penicillatus, 

 though he did have a skin of that species {loc. cit., p. 170). 



From what has been set forth above, then, it is clear, in com- 

 ^)aring the skull of Nannopterum harrisi with the skulls of other 

 Cormorants, that we may pay but scant attention to those of 

 the Urile series, while the direct comparisons should be made 

 with the skulls of the typical representatives of the Phalacrocorax 

 series, especially with those of P. penicillatus, P. carbo, P. 

 pcrspicillatus, P. auritus, and their immediate allies. The reason 

 for this will at once be apparent after comparing the skulls shown 

 on Plate 1. of the present paper and those on Plate XXIV. of 

 my " Osteology of the Steganopodes," where views of this part of 

 the skeleton of some five other species of Cormorants are pre- 

 sented, while still others occur in the text (pp. 184, 186). 



There appear to be four principal types of skulls met with in 

 the Phalacrocoracidce. The first of these may be designated as 

 the Urile type, wherein the skull is smaller than in the other?, of 

 a lighter and more delicate structure. The superior mandible is 

 rather lengthy, and the cranium compressed from above down- 

 ward. The occipital line and crest is somewhat reduced, and 

 the occipital style small. Over the parietal region, in the mid- 

 longitudinal line, the surface is smooth and the crest absent. At 

 its mesial inferior angle the lacrj-mial is connected with the 

 mesethmoid by a slender, bent bar of bone, which is larger and 

 stronger in the remaining three types. (In P. urile. No. 12,502, 

 Coll. U.S. Nat. Mus., there is a long, fx"ee, very slender vomer 

 present.) The foramen magnum is very large in proportion to 

 the size of the skull. The occipital line and crest meet in the 

 middle line at the site where the occipital style articulates. 



In the second type, which may be designated as the penicillatus 

 type, the skull is stronger and less delicately fashioned ; the 

 superior mandible is long and somewhat acute ; the cranium is 

 not nearly so much compressed from above downward. The 

 occipital line and crest are conspicuously developed, and the 

 interparietal crest is also present as a sharp, raised line, running 

 from the facet for the occipital style forwards to a point over the 

 centre of the cerebral casket, where it bifurcates and continues 

 forward and laterally either way to the apex of either squamosal 

 process. The occipital line and crest do not meet at the facet 



