﻿AO 



FOSSIL REPTILIA OF THE LIASSIC FORMATIONS. 



calcaneum ( c t), distally with the two outer bones of the distal row of tarsals. 

 The bone (d) which I have called " calcaneum" is the homotype of the cuneiforme 

 in the carpus, which it resembles in size and shape ; it articulates chiefly with the 

 astragalus ( a ) and ecto-cuneiforme ( ec ) ; it seems to touch the fibula (67) by a small 

 part of its periphery ; and in the angle between it and the fibula is wedged an ossicle (d'), 

 answering to the pisiforme in the wrist and to the apophysial part of the calcaneum 

 in the higher Vertebrates. The distal row of tarsals includes but three bones. The 

 first («), the homotype of the trapezium, I call " ento-cuneiforme it articulates with 

 the rudiment of the naviculare (*), and supports the metatarsal of the tibial or first 

 toe G). The next bone, " meso-cuneiforme " (cm), of larger size, supports the second 

 and part of the third metatarsal, articulates with the ento-cuneiforme (ti), and more 

 intimately and largely with the ecto-cuneiforme (ce)- This (ce) is the largest of the 

 three ; it supports the fibular half of the base of the middle metatarsal, the whole 

 of the base of the fourth metatarsal, and the tibial side of the base of the fifth meta- 

 tarsal; it articulates also with the meso-cuneiforme (cm), astragalus (a), and calca- 

 neum (d) ; it is plainly the homotype of the os magnum in the wrist. The homotype 

 of the unciforme, if it existed, must have articulated with the posterior or fibular 

 margin of the calcaneum, but it is not present in either limb. 



If we regard the largest of the distal tarsal series, supporting the fourth and part 

 of the third and fifth metatarsals, as the " cuboides," we must then consider its obvious 

 homotype in the wrist ( m ) to be the unciforme. The bone here called " meso- 

 cuneiforme" (cm), which articulates with both second and third metatarsals, will then 

 be the " ecto-cuneiforme," and the bone (a) will be the two other cuneiform bones con- 

 nate ; in like manner its homotype, called " trapezoides" in the wrist, which has a 

 similar relation to the second and third metacarpals, will be the trapezoid and trapezium 

 connate, but in that case the outermost ossicle (fig. 2, u) of the distal part of the 

 carpus would be a supernumerary without a name. I therefore prefer and adopt my 

 first homologies. 



The outer surface of the tarsals, except the middle of the calcaneum, is rugose. 

 The first metatarsal (ib., i) is 1 inch 9 lines in length ; it supports two phalanges ; 

 the total length of the toe, including the metatarsal, is 4 inches 9 lines. The length 

 of the second metatarsal is 2 inches 3 lines ; three of its phalanges are preserved ; it is 

 more distal in position than the first by about 4 lines. The middle metatarsal is 

 2 inches 5 lines in length ; four of its phalanges are preserved. The fourth meta- 

 tarsal, 4 inches G lines in length, has the fibular part of its base more extended, and 

 that margin of the shaft is more concave ; four phalanges are preserved, and the 

 length of the digit, including the metatarsal, is 10 inches. The fifth metatarsal is 

 2 inches 5 lines in length ; the tibial angle of its base is truncate, the fibular one is 

 much produced and tuberous ; the fibular margin is deeply concave ; only one phalanx 

 is preserved. 



