SHUFELDT : OSTEOLOGY OF THE STEGANOPODES 165 



The mid-trochlea is massive, not quite centrally located on the end of the shaft, 

 and is the next lowest in point of position. The highest of all is the external one, 

 and its outer part is produced the farther behind. 



On the anterior part of the shaft in front, in the groove extending up from 

 between the mid- and external trochlese, occur two perforating foramina. The lower 

 one makes its exit in the inter trochlear notch ; the other on the shaft above it. 

 Nearly all existing birds have only a single foramen at this point. It is even single 

 in Phalacrocorax. 



The free first metatarsal is large and strong, twisted upon itself, and with an elon- 

 gated transverse facet for articulation with the hallux. The skeleton of the j96s is 

 remarkably well developed. The phalangeal joints, arranged upon the plan of 2, 3, 

 4, 5 for hallux to outer toe inclusive, are stout and strong, and the terminal ungual 

 joints are, one and all, handsomely curved and sharply pointed at their extremities. 



We now pass to- the consideration of the osteology of the Cormorants, which it 

 will be found agrees in many particulars with the species of Darter we have just 

 been describing. 



Observations on tha SJceletoIogy of the PlmJacrocoracidse}^ 



A great many Cormorants of the world's avifauna, as I have before stated, belong 

 in this family, and as far as at present known it is the only one represented in the 

 United States, where, as heretofore noted, the nearly a dozen species and sub- 

 species it contains have all been restricted to the single genus Phalacrocorax. Cor- 

 morants are a good dea] alike in their osteology, and in this part of their anatomy, 

 too, they have a good deal in common with the Darters. To give the salient features 

 of the skeleton in this group I will draw upon the skeleton of P. nrile in particular, 

 as well as in general those of the collections of the U. S. National Museum, and 

 also republish a short description, together with the figures illustrating it, of P. per- 



'"In his recent (1899) Hand-List of Birds, Dr. K. Bowdler Sharps presents also a classification of the Cormorants 

 (pp. 232-235). They constitute the first group of his Order (XXIII.) Pelecaniformes, and all are relegated to the 

 tetmUy Phalacrocorncidte, and this latter is divided into four (4) genera, viz: (1) Phalacrocorax; (2) Pallasicarho ; 

 (3) Nannopterum, and (4) Actiornis. The first of these contains forty-two (42) species of existing cormorauts, and ten 

 (10) extinct forms ; tlie second is represented by a single extinct type, the P. perspicillaius ; the third contains only the 

 singular cormorant of Narborough and the Galapagos Islands ; while finally, the fourth genus is also represented by a 

 single extinct form, the yl. anglicus of Lydekker. In the United States we have some six (6) species and five sub- 

 species of Cormorants, all of the family Pludacrocoracidre. Through the constant energy and perseverance of Mr. Lucas, 

 a large proportion of these Cormorants are represented in the collections of the U. S. National Museum by their skele- 

 tons, and through his kindness I have been enabled to study and compare all this material in the revision of the present 

 memoir. The collection in question is now doubtless the finest of the kind in the world, and has in it the skeletons 

 of more steganopodous birds than that of any other in existence. 



