418 Prof. H, G. Seeley on Hortalotarsus skirtopodus. 



above downward and somewhat deeper than the distal end 

 of the metatarsal. 



The fourth metatarsal is perfect, 3y^o inches long, lyV i^cli 

 wide at the proximal end, which is compressed from above 

 downward and apparently only half as thick as the corre- 

 sponding parts of the second and third metatarsals. The bone 

 is flattened on the underside ; its sides are concave, so that 



Yj) inch, but widens 

 ^ Yu inch. The distal end 



also thickens, especially on the inner side. Three entire 

 phalanges are preserved in this digit and a fragmeut of a 

 fourth. They steadily decrease in length and width. Tiie 

 first is 1-^ inch long, transversely truncate proxiraally, ^ 

 inch wide at both extremities, with the sides concave and tlie 

 tinder surface concave and flattened, with the inferior margins 

 of the distal articulation prominent on the under surface. 

 The second phalange is fV inch long and y^ inch wide, of 

 similar broad depressed aspect to the first phalange, but differ- 

 ing in having the inferior proximal articular margin convex 

 from side to side ; a character also seen in the proximal end of 

 the third phalange, which is h^ inch long, h^ inch wide proxi- 

 mally, and narrower distally. On the inner side at the distal 

 ends there are large ligament-pits on the lateral border of 

 these three bones ; but the pit is absent on the metatarsal bone. 

 Similar pits probably exist on the more compressed external 

 margins of the phalanges, but are not exposed. 



The fifth digit is rudimentary. The fifth metatarsal has 

 its proximal end entirely beneath the fourth metatarsal, 

 except at the inclined external border. It is -^o- inch wide, 

 much depressed, Ijo inch long, with the sides concave and 

 converging distally to a widtii of less than fV inch. The 

 external border is about yo inch thick, and obliquely flattened 

 at the proximal end. One phalange was developed, which 

 is an oblong rudiment -So inch long and -jg" inch wide, which 

 has lost its extremity in removing the matrix. 



In so far as this foot can be compared it approximates 

 nearest to Dimodosaurus'^ ', but the metatarsals are less 

 robust and the phalanges more compressed from above down- 

 ward; and although the forms of the distal tarsals, especially 

 the cuboid, appear to have som.ething in common, the proximal 

 row of the tarsus is dissimilar. In the preservation of the 

 intermedium as a separate ossification not yet blended with 



* Gaudry, ' Fossiles Secondaires,' 1890, p. 219. It may also be com- 

 pared with the foot of Anchisaurus poli/zelus (Plitche), figured by O. C. 

 Marsh (Am. Jom-n. Sci. vol. xliii. pi. xvi., June 1892). See also Quart. 

 Journ. Geol. Soc. vol, xlviii., Proc. p. 191, and Proceedings for June 1892. 



