Prof. H. G. Seeley on Euskelesaurus Brownli. 331 



imperfectly preserved, as thougli there had been anchylosis 

 with the anterior margin of tiie fibula ; six inches below the 

 proximal end the shaft is ovate in section, 5 inciies from 

 back to front, 3j inches from side to side. Hence the expan- 

 sion of the proximal end is small, and the cnemial crest is 

 not much developed ; so that, although the proximal surface 

 is stout and wide, it does not differ materially from Masso- 

 sjiondylun, Agrosaurus, &c., and makes no approach to the 

 expanded tibia in Zanclodon, seen in the skeleton described 

 by Plieniiiger. 



The fibula has a front to back measurement of 5^ inches at 

 the proximal end ; its external surface is convex, being 2^ 

 inches thick in the middle and thinning to the lateral margins. 

 The internal surface is flattened on the posterior aspect, and 

 the anterior margin is slightly expanded, as though a film 

 from the tibia might be adhering to it. It rapidly diminishes 

 in size, for at 3 inches from the proximal end the transverse 

 measurement is 1^ inch and the back to front measurement 

 is 3 inches. The anterior and posterior margins are concave 

 in length and convex from side to side. 



Considered as a whole these bones are robust and charac- 

 terized by the fibula being expanded at both ends, so as to 

 be as deep as the tibial surface, with which it is in contact. 



The form of the distal end of the bone separates the tibia 

 widely from all genera with an ascending astragalus or co- 

 ossified intermedium. It seems a somewiiat more primitive 

 type than Ornithotarsus. 



I regard the cranial and pelvic evidence as supporting the 

 conclusion that characters in which this region of the skeleton 

 of Euskelesaurus diverges from Zanclodon are due to persis- 

 tence rather than modification of those parts of the bones 

 which are most liable to vary. 



The Hind Foot. 



M. Fischer figured {I. c. pi. x. fig. 6) a mass of bones 

 which I i-egard as the distal row of tlie tarsus. It shows three 

 bones in close contact, and there is a broken portion of a 

 metatarsal in connexion with the mass. Seen from the front 

 the transverse measurement is 6 inches and the vertical 

 measurement of the middle bone is 2^ inches. This is narrow 

 in proportion to the width of the tibia, but not quite con- 

 clusive as to whether four or five digits were developed. The 

 proximal convex surface corresponds to the concavity below 

 tlie astragalus. 



Of the digits, M. Fischer described two imperfect phalanges 

 and a more imperfect terminal claw-phalange. 



