226 Annals of the Carnegie Museum. 



inent. It is also deeply cleft for articulation with the head of the 

 fibula. The internal condyle is here markedly flattened. Above 

 them, the popliteal fossa, though circumscribed, is quite deep. It is 

 made so more particularly by the form of the internal condyle, which 

 has a sharp, elevated internal border carried up for a short distance 

 upon the shaft, and a ledge-like connection with the external condyle, 

 the flat upper surface of which forms the distal side of the popliteal 

 fossa. The patclhe are not present in my specimen, and Tantalus 

 may either not possess those sesamoids, or they may have been lost. 

 I am inclined to believe the species does not have them, and they are 

 not present in P/egadis ii'iiaraufia. 



The wonderfully long shaft oi tibio-tarsus is perfectly straight for its 

 entire continuity until we reach a point immediately above the con- 

 dyles of the distal extremity ; at this point it makes barely a perceptible 

 turn forwards. The posterior and lateral aspects of this shaft form 

 one continuous rounded surface, while the anterior aspect is nearly 

 flat, with a gradual and very slight inclination to become longitudin- 

 ally grooved at the junction of the lower and middle thirds for a dis- 

 tance extending over about 3 centimeters. On the summit of the bone 

 the articular surface is nearly level and the entire width of the cnemial 

 crest is developed but a short distance above it. Pro- and ectocne- 

 mial processes are produced hardly at all down upon the front of the 

 shaft, but otherwise they are in no wise reduced, and exhibit the 

 usual ornithic characters. Almost immediately below the external one 

 we find the fibular ridge commencing, and thiS; after extending down 

 the shaft for a distance of about 3 cm., terminates somewhat abruptly. 

 At the distal extremity the condyles are of a size in proi)ortion with 

 the other parts; they have the ordinary reniform outline ; and one of 

 them is no lower on the shaft than the other. They project beyond 

 the latter about as much posteriorly as they do in front. But the in- 

 tercondyloid groove is decidedly shallow both below and in the former 

 situation, .\nteriorly, however, it is very deep, and at its upper part 

 here forms a distinct rounded concavity. This is intended for the 

 reception of the conspicuous and rounded process situated on the an- 

 tero-median aspect of the summit of the tarso-metatarsus, when that 

 bone is powerfully flexed upon the leg. Above the just-mentioned 

 concavity, the bone also juts out a little ways, thus forming an abut- 

 ment to add additional security to the articulation. Just internal to this 

 is the very small lower aperture of the tendinal canal. The proximal 



