664 



PEOP. H. Gr. SEELET 01$ THE EEPTILE 



oblique moderately elevated muscular ridge, which extends for about 

 3| inches across the middle of the shaft from near the inner side 

 proximally towards the outer side distally ; and though the whole 

 superior surface, except the expanded crest, is roughened with mus- 

 lar lines, another fainter ridge may be traced running straight dis- 

 tally from the proximal termination of the oblique ridge. Imme- 

 diately below the proximal articulation in the middle of the shaft is 

 an elevated muscular boss about inch in diameter, which, as 

 preserved, is subcircular. The thickness of the shaft at its inner 

 margin is 1 T ^ inch, and at its outer margin inch. The radial 

 crest thickens towards the proximal surface, and curves a little 

 upward. The outliue of the fractured proximal end is somewhat 

 boat-shaped and compressed (fig. 3). This humerus is quite distinct 

 in character from any form of which I have any knowledge. 



Femur. 



The right femur (PI. XXXI. fig. 5), found in 1876, is 10-X- inches 

 long. The left femur (PL XXXI. fig. 4), found in 1877, is hardly 

 more than 10 inches long. This difference is apparently due to the 

 different ways in which the bones are compressed. They are both 

 in the same state of mineralization, of a rich chocolate-brown colour, 

 and quite free from matrix, which has been removed by Professor 

 Suess. The bones belong to a somewhat distinct type; they offer many 

 resemblances, as Professor Suess pointed out to me, to Cryptosavrus 

 of the Oxford Clay, but are more slender. They therefore show the 

 typical characters of Dinosaurs, though there is a difference from 

 all English genera in the proximal anterior trochanter not being 

 separated from the shaft ; and there is a remarkable development of 

 muscular ridges on the bone, one of which extends on the proximal 

 posterior face (fig. 4) in a curve upward and outward from the small 

 middle trochanter on the inner margin of the shaft to the outer 

 and external margin of the proximal articulation. It is impossible 

 not to recognize the similarity of this strong muscular ridge to the 

 ridge seen on the corresponding aspect of the mammalian femur; 

 and if this coincidence be admitted, it goes far to prove that the 

 middle trochanter, which is the most distinctive mark of the femur 

 of a Dinosaur, is homologous with the inner or lesser trochanter of 

 man ; and so far it would seem rather to imply a foreshadowing 

 of a mammalian plan of muscle-arrangement. A similar muscular 

 attachment to this may be observed in Crocodiles above the middle 

 of the shaft. Prom it an intertrochanteric muscular ridge extends 

 to the position in which the proximal trochanter of Dinosaurs 

 is seen when it is developed. The shaft is most constricted in its 

 distal third, where there is a slight flexure bending the distal arti- 

 culation backward ; both articular ends appear to have been highly 

 cartilaginous, since they are marked with ramifying furrows and 

 occasional pits. As is usual with cartilaginous surfaces, the arti- 

 cular margin is sharply defined. 



The proximal articular surface is best preserved in the right femur, 



