Vol. XV. I ':^iivi--iAAyi', Osteology oj Huyyis's Coymordn/. 103 



in most of the species of the f^emis Phalacrocorax. In no Cor- 

 morant, however, possessing the full power of flight are they so 

 far apart, though we find a certain degree of separation in some 

 species, as in P. urile and P. pelagicus (No. 19,655, Coll. U.S. Nat. 

 Mus.), while in others a slight decussation is to be observed, as 

 in P. auritus. Finally, in other species the mesial, inferior angles 

 of the coracoids are simply in contact when duly articulated in 

 their sternal grooves as in lite [P. magellanicus). 



The Shoulder-Girdle (Plate XVI., figs. 8-11, 14. and 15).— In 

 most of the skeletons of Nannopteriim at hand the os Jurcula is a 

 broad, U-shaped one, possessing most of the characters of the 

 bone as seen in Cormorants generally. The breadth of the U 

 varies in different specimens ; for example, in No. 19,721 the 

 clavicular heads are 67 mm. apart, while in No. 19,628 they are 

 but 54 mm., and in No. 19,719, a large bird, they are 74 mm. 

 apart. Probably these figures represent the extremes in this 

 matter. Either clavicular head is enlarged in the same way as 

 it is in all true Cormorants, there being a short scapular process 

 above, which, by the way, does not reach the scapula in the 

 articulated skeleton, and an abutment bearing on its posterior 

 aspect a flat, articular facet of sub-circular outline for the head 

 of the corresponding coracoid. 



The main arc of the os fitrciila exhibits some, though not a great 

 deal of, reduction, and this likewise varies, being less in some 

 individuals than in others. Some Cormorants have the clavicular 

 arc of the os Jurcula doubly as stout as it is in any specimen of 

 Harris's, as, for instance, P. auritus (No. 19,262, Coll. U.S. Nat. 

 Mus.), where, likewise, it seems to be, to a certain extent, 

 pneumatic. Every vestige of a hypocleidium in the os furcula of 

 Nannopterum has disappeared ; in the articulated skeleton, as in 

 life, the bone simply rests against the smooth surface on the 

 anterior face of the rudimentary keel of the sternum, being held 

 in position by binding ligaments in the living bird. All other 

 Cormorants, in so far as 1 have examined them, possess some sort 

 of a hypocleidium wherewith to meet the carinal angle of the 

 sternum in articulation (fig. 14, Plate XVI.) 



A coracoid of this flightless Cormorant has a length, generally, 

 of about 66 millimeters, though it may be much shorter, as it is 

 in No. 19,628, where it is but 58 mm. long. Measuring its inferior 

 angles from apex to apex, it may be broader transversely — 

 everything else being equal — than is the coracoid in some other 

 Cormorants. For example, the distance just mentioned 

 measures 32.5 mm. in No. 19,721 of the series of Harris's Cor- 

 morant, while in an adult skeleton of P. auritus (No. 19,262) the 

 same Hne equals 30 mm. 



The upper extremity of the bone, which articulates with both 

 the OS furcula and the scapula, presents the characters found there 

 among Cormorants at large, there having been no change beyond 

 a certain amount of shrinkage (Plate XVI., figs. 8 and lo). The 

 shaft of this coracoid, however, has become, through a uniform 



