BETWEEN TYPICAL REPTILES AND OTHEE ANIMALS. 163 



bones have mucli the same relative proportion to each other in 

 the two groups of animals. 



The long carpal bones of the Crocodile are not comparable to 

 the short carpals of birds, which have the distal carpal row anchy- 

 losed to the metacarpus. 



The five free metacarpal bones of the Crocodile are different 

 from the three anchylosed metacarpals of birds ; and the phalanges 

 are very different, though in the Crocodile the three fingers most 

 developed are those on the inner or radial side, which represent 

 the digits of the bird. 



The Cx'ocodile's os innominatum is made up by elements com- 

 parable to those of birds, but differently proportioned. They 

 remain unanchylosed with regard to each other, and are not 

 anchylosed to the sacral vertebrae, as they usually are in birds, 

 though they remain separate from the sacrum in the Penguin. 

 In birds the ilia are always much more prolonged both anteriorly 

 and posteriorly, and have the long axis of the bone identical with 

 that of the sacrum, which is not the case in the Crocodile ; in the 

 bird the ilia approximate dorsally, in the Crocodile they approxi- 

 mate ventrally. The ischium and pubis are much more slender 

 in birds than in Crocodiles, and less elongated ; they are directed 

 backward and are close together, while in Crocodiles the bones are 

 rather directed forward, and expand considerably at their distal 

 ends ; and the pubis does not meet the ilium, but is supported on 

 the anterior process of the ischium ; hence in Crocodiles there is 

 no obturator foramen. The articulation in the Crocodile's pelvis 

 would be perforated as in birds, if the forward process of the 

 ischium met the ilium, which it does not quite do. The bird in 

 which these bones are best comparable to the Crocodile's is the 

 Emu. 



The femur in the Crocodile differs chiefly from that of the bird 

 in the proximal end not being in the same plane with the distal 

 end, owing to which, the bone has a twisted aspect. The proximal 

 articulation in birds is not so globular, nor the end so massive ; 

 nor is the ridge, which looks outward and backward at the proxi- 

 mal end, so much developed. The bird is wanting in the powerful 

 muscular attachments which make a sort of trochanter on the 

 inner side of the upper half of the femur of the Crocodile. At the 

 distal end the femur of the Crocodile resembles the bird's in having 

 the outer condyle the larger ; there is a similar small process on 



LINN. JOUKN. — ZOOLOGT, VOL. XII. 12 



