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cnemial ridge: this is short, and descending obliquely inwards terminates or subsides 
upon the prominent fore part of the tibia about an inch below its upper angle. The 
procnemial ridge has an equally short origin, which is oblique and parallel with the ecto- 
cnemial ridge: it is broken in the specimen under description, but from the analogy of 
the Brachypteryx probably projects far forwards: where it subsides at the inner side of 
the tibia there is a tuberosity, from which a low ridge extends bounding internally the 
fore part of the tibia as far as the canal for the extensor tendon. The fibular ridge is 
well-marked ; it begins on the outer side of the shaft one inch below the epicnemial 
ridge, extends nearly two inches down the shaft, and after a smooth tract of half an 
inch, reappears as a rough tract of an inch and a half in extent: a low narrow ridge 
is continued thence to the outer side of the fossa, lodging the extensor canal. The shaft 
of the tibia is compressed from before backwards, is smooth and rounded on the inner 
side which is thicker than on the outer side. The hinder and under part of the distal 
articular surface is convex from behind forwards, slightly concave from side to side, in- 
creasing in breadth as it extends forwards, and bounded laterally by two prominent 
ridges: the division of this surface into condyles is limited to its fore part, where they 
project forwards, are of small size, and are divided by a very wide concave interspace, 
immediately above which is the bony canal for the extensor tendons. The distal end of 
the tibia is expanded chiefly at its inner side, towards which it seems to be slightly bent. 
The tarso-metatarse (Pl. LI. fig. 5) a little exceeds the femur in length: its proximal 
condyloid cavities are small and widely separated by a large intercondyloid prominence, 
and a non-articular tract behind extended upon a calcaneal process: the entocondyloid 
cavity is as usual the deepest. The calcaneal process is simple, imperforate, and sub- 
sides eight lines below its upper end upon the back part of the mesometatarse, The 
concavity on the inner side of the calcaneal process is bounded internally by a ridge 
continued from a tuberosity behind the entocondyloid cavity about two-thirds down the 
shaft, below which is the well-marked oval depression for the back-toe (1). A small 
foramen, indicating the interosseous space between the inner and middle metatarsals, 
opens into the upper part of the concavity below and at the inner side of the cal- 
caneal process. On the outer side of that process, but at a lower level, is a similar 
remnant of the primitive space between the middle and external metatarsals : both these 
foramina unite as usual into a single median foramen at the fore part of the proximal 
end of the bone. A deep and wide concavity occupies the upper half of the fore part 
of the tarso-metatarse: it is gradually filled up by the advance forwards of the middle 
metatarsal element, which is placed as usual rather obliquely between the outer and 
inner elements, A slight groove between the distal portion of the middle metatarsal 
and the outer one, leads to the canal for the transmission of the adductor tendon of the 
fourth toe. The outer and inner trochlez are nearly of equal extent, the outer one being 
a little longer or lower: the middle trochlea is the longest as well as largest : it does not 
advance so far forwards as in the Aptornis: each condyle is slightly grooved. 


