440 CROCODILIA CHAP. 



and Gavials is composed of twenty -six precaudal vertebrae 

 (namely, nine cervical, fifteen thoracic and lumbar, two sacral), 

 and about thirty-four to forty or more caudal vertebrae. Indi- 

 vidual variations, including lop-sided attachment of the iliac 

 bones, are by no means uncommon. 



The sternum remains cartilaginous. It consists of an anterior 

 rhomboid portion, which carries the coracoids and two pairs of 

 ribs, and a posterior longer and narrower portion formed by the 

 median fusion of the next following five or six ribs. Posteriorly 

 the sternum bifurcates, each half carrying two or three ribs, of 

 which the last sometimes loses its proximal connexion, and thus 

 appears as a xiphisternal process. Yentrally, upon the anterior 

 part of the sternum lies the longitudinal, originally paired, 

 episternum. The shoulder -girdle consists of the coracoids and 

 the scapulae, which fuse with each other into one bony piece 

 on each side. A pre-coracoid is indicated in fossil forms by a 

 notch in the coracoid. 



The space between the posterior end of the sternum and the 

 pubic bones is occupied by the so-called abdominal sternum, com- 

 posed of seven pairs of ossifications, resting upon the ventral side 

 of the rectus abdominis muscle. Each pair consists of two closely 

 apposed pieces, while the right and left remain separate in the 

 median line. The last pair is much stronger than the rest, is more 

 deeply imbedded in the rectus muscle, and is loosely connected 

 with the anterior margin of the two " pubic " bones. 



The limbs are built upon the typical terrestrial pentadactyle 

 type, but were in the Jurassic species undoubtedly more adapted 

 to swimming locomotion. The fore-limbs were conspicuously 

 shorter and smaller than the hind-limbs, and it is only since 

 Tertiary times that the difference has decreased to a great 

 extent. Ulna and radius remain separate. The proximal 

 row of carpal bones consists now of the ulnare and radiale, 

 both strong and distinctly elongated. On the outer side, be- 

 tween ulna and ulnare, lies a pisiform bone. Upon the 

 radiale follows a compound bone, often imperfectly ossified 

 towards the median side, and consisting of the first distal 

 carpal, the centrale, and the intermedium. The third, fourth, 

 and fifth carpals are fused into one mass. The second distal 

 carpal remains separate. All five fingers are present and well 

 developed. The number of phalanges of the pollex is two, of 



