518 PROCx^lEDINGS OF THE NATIONAL MUr.EVM. vol.54. 



shaft immediately below and behind the peroneal ridge, 3 milli- 

 meters distant from its base. The fibula is lost, but was ankylosed 

 by a slender attachment at its distal end to the shaft of the tibia. 

 The lower portion of the tibio-tarsal shaft is broad and flattened 

 on its anterior surface with the usual osseous bridge under which ran 

 the tendon of the muscle extensor digitoi'utri communis. The distal 

 condyles are large and heavy, with a broad sulcus between them 

 anteriorly. On the articular surface is a slight median ridge. 



Measurements. — Femur, Cat. No. 225845, U.S.N.M. (type) : Length, 

 76.5 mm.; transverse diameter through center of head, 17 mm.; 

 transverse diameter through medullary foramen, 7.5 mm.; inter- 

 condylar diameter,^ 16.6 mm. 



Tibio-tarsus, Cat. No. 225845, U.S.N.M. : Length, 110 mm. ; breadtli 

 through lower end of peroneal ridge, 9 mm.; greatest breadth 

 through condyles, 12.5 mm.; length of articular face of peroneal 

 ridge, 17 mm. 



Remarks. — This bird is represented by portions of eight bones, all 

 from the posterior limb — namely : Two nearly complete right femora, 

 the proximal portion of a left femur from a smaller individual, a 

 nearly complete right tibio-tarsus, the distal end of two others and 

 portions of two left tibio-tarsi, one of which lacks the anterior end, 

 while in the other the condyles are missing. 



The relationships of this remarkable rail must remain for the 

 present somewhat obscure. It might be supposed that it would 

 resemble Aramides closely, but this is not the case. The bones at 

 hand are equal in length to the same bones in Aramides cayanea but 

 are much more robust. There is no skeleton of the large A. ypecaha 

 available, but there are several skins in the collections of the United 

 States National Museum in which the knee joint has been disarticu- 

 lated so that the tibio-tarsus is complete. In these the tibio-tarsus is 

 from 20 to 25 rmn. longer than in Nesotrochis dehooyi^ while the inter- 

 condylar breadth at the distal end is slightly less, though this region 

 is covered by skin. From this it is seen that the proportions of the 

 two birds are entirely different. 



In other rails available that part of the femoro-tibial depression 

 above the inner anterior crest of the tibio-tarsus slopes inward and 

 downward, and has no defined inner margin ; there is also a terminal 

 decurved hook on the outer anterior crest that is not present in Neso- 

 trochis, though this may have been slightly developed as specimens 

 available show some wear here. The distal ridge found on the poste- 

 rior articular surface of the *tibio-tarsal condyles in Nesotrochis is 

 absent in other rails. The slight lateral rugae on the femoral shaft 

 are well developed in Aramides and are lightly indicated in a speci- 

 men of Tribonyx mortieri. 



1 Not exact, as lower ends of condyles are missing 



