Vul. XIX. I tjiiui'icLDT. Mdleyial fur a Sliuly of the Megapudiida\ 1-5 



nearly straif^ht, cxliibiting but a very slight convexity down its 

 anterior surface. For its entire length, the sliaft is very slightly 

 compressed in the antero-posterior direction. 



Distally, the valley between the reniform condyles is rather 

 wide ancl shallow, becoming narrow only in front, where above 

 them, and slightly to tlic onter side, there is a strong, transverse 

 little bridge of bone, under which, as is the case in so many birds, 

 some of the tendons of tlie leg pass. 



High up on the outer side of the shaft of tlie ti bio-tarsus we 

 have the low, feeble crest — nearly two centimeters in length — for 

 articulation with the fibula. Below this, the latter bone, as a 

 very slender bone, is carried down the side of its companion in 

 the leg to a point about a centimeter and a half above the outer 

 condyle. Above its articulation with the tibio-tarsus the fibula 

 rapidly increases in size, and its rather bulky, triangular head is 

 much compressed in the transverse direction. As usual, it 

 articulates in a groove intended for it, found traversing the 

 external condyle of the femur in the antero-posterior direction. 



There is a large, semilunar sesamoid articulating with the hinder 

 aspect of the inner condyle of the lower end of the tibio-tarsus ; 

 it is held in its place by strong ligaments. 



Turning next to the tarso-metatarsiis, it is to be observed that 

 for its size it is quite as massive as the other bones of the leg 

 already described above. Its rather broad shaft is very straight, 

 and considerably compressed from before, backwards. Its 

 grooving for the tendons of muscles is but faintly marked ; the 

 longitudinal excavation anteriorly at the upper end, so deeply 

 marked in many birds, is here very shallow, and the elongate 

 tubercle for the insertion of the tendon of the tibialis anticus 

 muscle lies, not within it, Imt is situated on its inner edge. The 

 two usual perforating foramina occur at their places just above 

 this tubercle in the middle line. Extending over the shaft all 

 around, the head of the bone is large, and presents at its summit 

 the usual concavities and elevations to accommodate in articula- 

 tion the condyles of the tibio-tarsus. The inner part of the shaft, 

 down longitudinally for about one-third its length from the 

 proximal extremity, is thin and very sharp. This is by no means 

 frequently seen in the tarso-metatarsi of birds. 



The hypoiarsiis has an unusual form ; it is short and somewhat 

 l)ulky. Postericndy, it is capped off with a flat piece of bone that 

 is flusli with the process externally but projects much beyond it 

 internally. Its flat surface looks directly backwards, and the 

 whole piece — nine millimeters long and three wide — is of an 

 elliptical outline with broadly rounded ends. Directh^ in front 

 of this the hypotarsus is longitudinally pierced by a single, 

 cylindrical, completely enclosed passage for the transmission of 

 tendons. On the outer aspect, two ridges- -an anterior short one 

 and a longer posterior one--clivide the surface into three longi- 

 tudinal grooves for tendons of muscles. In the middle line, 

 posteriorly, tlie l)ase of tlie hypotarsus is carrit'd down on the 



