1. XV. "I 



1915 J 



Shufkldt, Osteology of Harris's Cormorant. Ill 



others it is longer and considerably more slender with respect to 

 its shaft, and so on through the family. 



Nannopterum harrisi })ossesses a rather short, very stout, 

 straight, broad, antero-posteriorly flattened tarso-metatarsus, with 

 large, prominent, distal trochlea;, which lie nearly in the same 

 plane, though the middle one is somewhat the lowest. The 

 anterior aspect of the shaft is excavated above, which excavation 

 imperceptibly merges on to the shaft as a shallow, longitudinal 

 concavity, as far as the large, circular foramen below, which in 

 life transmits the anterior tibial artery. 



The outer side of the shaft is also longitudinally grooved for 

 the passage of certain tendons to the foot. Posteriorly, the shaft 

 is flatter, though a little less so internally, where, at its lower 

 third, is attached by ligament the rather large first or accessory 

 metatarsal the enlarged distal end of which articulates with the 

 first joint of hallux. 



At the base of the excavation at the upper third of the bone 

 in front there is to be observed the usual pair of foramina, placed 

 closely side by side. They pierce the shaft as usual, their 

 posterior exits being not far apart, one on either side of the large 

 quadrate hypotarsus. This latter springs from the inner mesial 

 aspect of the shaft above, being a large quadrate osseous lamina, 

 finished off posteriorly by an expanded cap of bone, rounded above 

 and pointed below, flat behind, and with its margin protruding 

 all round — this finishing-off piece itself being at right angles to 

 the hypotarsal plate proper (Plate XIX., fig. 23). In Harris's Cor- 

 morant it extends below the latter : but this is not the case in all 

 Cormorants — such species as Pallas's, P. iirile, and many others 

 being exceptions to it. 



Then to the otiter side of the hypotarsal plate in Nannopterum 

 we find one large groove for tendons, and external to it one or two 

 very shallow, and very indefinite others. There are no piercing 

 foramina, while in Pallas's Cormorant, in P. punctatus, and 

 doubtless in others, one very distinct foraminal, tendina) passage 

 passes through the hypotarsus longitudinally. This is the case 

 also in P. iirile and P. auritus. 



The condylar cavities on the summit of the bone are, as we 

 might suspect, extensive — the inner one being the larger as well as 

 the deeper of the two, while a big, intercondylar tubercle stands 

 between them in front. Postero-externally, the outer of these 

 two articular areas is drawn out into a distinct apophysis, which 

 is present in most other Cormorants. 



In pes the joints are long and somewhat flattened from above, 

 downwards, except in the case of the long, curved joint of hallux. 



The ungual joints, though of fair size, are of a feeble pattern, 

 as is the rule in the case of most swimmers among birds (fig. 23, 

 Plate XIX.) All the basal joints of the anterior toes are nearly of 

 a length, each averaging about 26 mm. from base to distal 

 trochlea : this is more or less true of other Cormorants. 



