Prof. H. G. Seeley on Hortalotarsus skirtopodus. 417 



The intermedium (or naviculare) is a small ossification 

 which lies upon the anterior and superior external margin of 

 the astragalus, appearing in front as a small ovate ossicle 

 beneath the inner angle of the fibula, which may be produced 

 upward as a thin film in the outer part of the suture between 

 the astragalus and tibia. 



The separate condition of the astragalus and calcaneum is 

 paralleled in Omithotarsus and many American types. The 

 intermedium is so small that it might be easily overlooked or 

 lost in removing the matrix. It may hereafter be found in 

 Saurischia, in which the tarsal elements remain separate. 

 It is not recognized in Euskelesaurus. 



While the proximal row of the tarsus is in close contact 

 with the tibia and fibula, the distal tarsal row is in associa- 

 tion with the extremities of the metatarsus, upon which the 

 bones of the fore leg are pressed down in close contact. 

 There were probably four bones in the distal tarsal row, the 

 three cuneiform and cuboid ; but, if so, the first two cuneiform 

 bones are lost with the metatarsals. The third cuneiform is 

 imperfect and gives attachment to the third metatarsal ; and 

 the cuboid, which lies below the calcaneum and part of the 

 astragalus, articulates with the fourth and fifth metatarsals. 

 A vertical division like a suture passes through the middle of 

 the cuboid ; but there is no conclusive evidence that it is not 

 a fractm-e. 



In transverse measurement the cuboid is 1^^^ inch; it is 

 wedge-shaped, narrower on the outer proximal margin {^ 

 inch) than on the inner side, which is less than 4 inch wide 

 on the proximal surface, which is convex from front to back, 

 concave on the anterior and posterior borders, and rounded at 

 the two extremities. It is fully ^ inch deep ; but the distal 

 surface, which is smaller than the proximal, is not exposed. 

 No trace is preserved of the first digit. 

 Of the second digit only an impression remains of the 

 proximal half of the metatarsal, with a small portion of its 

 proximal articular surface indicating 2-^ inches of the length 

 of the bone, which was flattened on the superior surface. 



The third metatarsal is 4 inches long, with the bone pre- 

 served at the two extremities. It obliquely underlaps the 

 second metatarsal at the proximal end, is flat on the upper 

 surface, expanded at the distal end, and convex from above 

 downward on the distal articular surface ; but the convexity 

 does not extend on to the inferior distal surface. A large 

 ligamentous pit is excavated on the external margin. Only 

 a small part of the proximal phalange of this digit is pre- 

 served, which shows its articular surface to be concave from 



