718 CBANIUM OF PALLAS'S CORMORANT— LUCAS. vol. xviii. 



Pallas's Cormorant shows a marked diflereuce from all others exam- 

 ined 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-shai)ed 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 V. perspicUlatns there is a lateral ethmoid plate, complete 

 save for an opening above, being the retention by ossification of a car- 

 tilaginous plate found in the nestling of P. urile before the nostrils 

 have become closed. The maxillopalatines are also slightly better 

 developed than in any existing cormorant, and while tlie diifereuce is 

 small, still it does exist, and here again it is seen by comparison to be 

 the development of a character found in young birds. 



Difterences exist between P. perspiciUatKs and other cormorants by the 

 presence of a narrow bar of bone forming two precranial cavities where 

 but a single oj)ening exists in allied species, and in the comparatively 

 small size and regular lyrate form of these openings. From these con- 

 ditions it will be seen that there is in the cranium an excess of ossifi- 

 cation over that found in other cormorants. While no bar of bone has 

 been found in other species, there are hints of it in some, thus, F. peni- 

 cillatus and P. magellanicus, in the shape of a little bony spike running 

 upward from the alisphenoids, and it is not impossible that the com- 

 plete bar may be found in some very old individual. This is the more 

 probable because in the young, of P. urile at least, there is a bar of 

 cartilage occupying the place of the bar of bone found in Pallas's Cor- 

 morant. 



The sternum (No. 19417, U.S.oS^.M.) found with the present series of 

 bones is important, as its size indicates it to be that of a male, and 

 shows the sternum previously described to have been that of a female, 

 or possibly even that of a male of P. urile. It is very much larger 

 than any sternum of P. urile, and much larger even than the large 

 specimen of P. carho, used for comparison.^ The present sternum is 

 thus in harmony with the other bones, and aids materially in emphasiz- 

 ing the superior size of P. perspicillatus. 



The appended tables give the measurements of the cranium and ster- 

 num here described, compared with the corresponding parts of other 

 species. The measurements of the previously described sternum, 

 ascribed to P. perspiciUatus, are repeated and an error of the first- 

 given table corrected. The length from anterior end of carina to end of 

 mesoxiphoid is said to be 101 mm., when it should have been 90 mm. 



Unfortunately the skull of P. carho now available is smaller than 

 that of the individual used as a term of comi^arison in the previous 

 paper- on Pallas's Cormorant. 



iProc. U. S. Nat. Mus., XII, 1889, pp. 88-94. 

 -Loc. cit. 



