AND AVES OF NORTH AMERICA. 



107 



The direction of the condyle in these genera indicates the articulation of the distal tarsal and metatarsal elements 

 to have been at a considerable angle with the shank of the leg, and that the direction of the whole foot was oblique 

 as in the birds. As the type is in respect to this articulation between that of Iguanodon and that of Compsognathus, 

 we may probably attribute to it a length of metatarsus intermediate between those possessed by these two, a proposi- 

 tion confirmed by the metatarsals of an allied species, L. macropus m, preserved in the Museum of Rutger's College, 

 New Brunswick, and described by Leidy. These are double the length of the slender phalanges and near one-hall' 

 that of the tibia, slender and pneumatic. 



Among the remaining Dinosauria the two rows of tarsals are distinct and oomposed of several elements ; one of 

 the proximal scries articulating with the largely developed fibula as in the Sauria proper. For this I have proposed 

 the name Orthopoda as (be tarsal and metatarsal elements do not seem to have been oapable of the same degree of 

 Jlexuro on each other as in the Gkraiopoda and Bymphypoda. 



Phalanges, — No. 1. An ungual phalange of remarkable size and destructive use. The depth at the proximal 

 articulation is about the same as in Megalosaurus bucklandii (two inches without inferior tuberosity), but the 

 length is considerably greater. Form everywhere compressed, especially at tip; rounded above. Kelowthe articu- 

 lating surfaces is the point of insertion of a, large flexor tendon, a, flattened subglobular process, separated by a groove 

 except in front. The groove extends on each side distally on the middle, to the tip. The general form is not unlike 

 that of a rapacious bird, but it is more compressed. 



Length on convexity, 



Chord from articulatory surface, 



Inches. 



Surface slightly striated at the base on one side. 



No. 2. Penultimate. Proximally higher than broad, distally broader than high ; two elevated articular surfaces 

 proximally, distal condyles separated by a, deep groove and much prolonged inferiority ; a fossa on each side eccentric 

 to the condyle. Superior outline straight, inferior descending behind. 



No. 3. Also penultimate, is flatter and more parallelogram mic in section than the last. 



No. 4. Antepenult? more; cylindrical, condyles broken. 



Length, No. 3, 

 Proximal elevation, 



" breadth below, 



Breadth shank below, 

 Distal width, 



" " of condyles below, 



No. !?, proximal breadth below, 

 Breadth shank below, 



Terminal and inferior breadth distal condyles. 

 No. 4, length, 



Inches. 



4.75 



1.75 



1.75 



1.25 



1.25 



1.75 



2.125 



1.50 



1.875 



G. 



Another phalange of a, much larger individual pertaining perhaps to Laelaps, which was accompanied by a plate- 

 like bone, is thus described in the Proceedings Academy Natural Sciences, 18(50, p. (i : 



"Dr. Leidy directed the attention of the members to the specimen of a large phalanx of an extinct reptile, pre- 

 sented this evening by Dr. W. Spillman of Columbus, Miss. It was derived from the cretaceous formation in the 

 vicinity of the latter place, and is remarkably well preserved. It is a first phalanx, and in general form resembles 

 the corresponding phalanges of the Alligator, but is proportionately more robust. The proximal articular surface is 

 moderately concave, somewhat uneven ; and in outline is tianserve oval with the lower side Hat ; the distal extremity 

 is provided with a trochlear articular surface and deep pits literally for ligamentous attachment. The animal to 

 which the bone belonged is unknown; it may be conjectured to have appertained to the fore foot of lladrosaurus. 

 The measurements are as follows : 



