FROM THE LOWER LIAS OP CHARMOTJTH. 



463 



which is distinctly ridged ; the entirely compressed left ulna is 

 ridged all over ; and this leads one to suggest that the ridges on fossil 

 bones may in some cases have been subsequently produced by me- 

 chanical pressure. Let the soft cancellous interior of a bone be 

 crushed together, and the denser outer layers, in adapting them- 

 selves to a more circumscribed area under pressure, may possibly 

 become finely wrinkled, and thus give rise to a spurious appearance 

 of ridges. 



Tlie Carpus. 



The carpus, 7-25 inches in breadth, consists of two rows cf three 

 bones each, which diminish in size from the ulnare to the radiale. 

 They are polygonal bones, with the dimensions given in the table 

 below. In the left manus the distal row of carpal bones alone 

 bears the fingers, the radiale carrying one, the intermedium and 

 ulnare two each. In the right manus the ulnare of the proximal 

 row appears to bear one finger, the ulnare of the distal row two, 

 the distal intermedium one (but it contributes a small facet for the 

 adjoining digit of the ulnare), and the distal radiale, as in the left 

 manus, one. 





Length. 



Breadth. 





Eadial. 



Inter- 

 medium. 



Ulnare. 



Eadial. In 1 t . er - 

 , medium. 



I 



Ulnare. 



Proximal series... 



1-6 

 1-8 



23 

 14 



2-65 

 2-9 



2-15 2-5 

 2-1 i 1-8 



2-75 

 2-1 



The Manus. 



The hand, where broadest, is 8-5 inches across. It consists of five 

 digits ; the first, with five phalanges, is incomplete in both hands ; the 

 rest are complete in the left manus — the second, third, and fourth 

 having nine, and the fifth eight phalanges. The third and fourth 

 fingers are the longest. The phalanges have the usual form, a 

 compressed hour-glass outline, — except the most distal, which is 

 triangular, and apparently equivalent to the proximal half of one 

 of the other phalanges, the distal half being suppressed : it has 

 much the appearance of an ungual phalanx, and may very well 

 have borne a nail. 



The measurements of the phalanges are averages of those of the 

 right and left manus, and in the case of the breadth, of the distal 

 and proximal ends of each phalanx. 



