AND ON THE EVOLUTION OF THE CROCODILIA. 425 



The dorsal scutes are angulated and longitudinally keeled on their 

 free surfaces; the ventral scutes are flat, and formed of a single 

 ossification. 



The free surfaces of the scutes have a deeply pitted or grooved 

 sculpture. The vertebrae (except doubtless the atlas and axis) are 

 amphicoelous, the anterior and the posterior surfaces of their centres 

 being alike slightly concave. The transverse processes resemble 

 those of Crocodiles ; and, as in some recent Crocodilia (e. g. G. nilo- 

 ticus) and in Belodon, those of the anterior thoracic vertebrae are 

 inclined upwards. 



The transverse processes of the lumbar vertebrae, of which there 

 were not fewer than two, are long, broad, and directed horizontally, 

 those of the last lumbar vertebra being wider at their outer than 

 their inner ends. 



The sacrum consists of two unankylosed, amphicoelous vertebrae ; 

 and the ends of the sacral ribs are remarkably wide — more so in 

 proportion than in any Crocodile known to me. 



The centrum of the first caudal vertebra is amphicoelous. The 

 skull is produced into a slender rostrum ; and the rami of the man- 

 dible are united in a long symphysis. The posterior nares are situ- 

 ated far forward, as in Lizards ; and neither the palatine nor the 

 pterygoid bones unite to prolong the nasal passage backwards and 

 give rise to secondary posterior nares, as in existing Crocodiles. In 

 the mode of formation of the proper posterior nares, however, Stago- 

 nolepis conforms to the Crocodilian type. 



All the teeth which I have reason to refer to Stagonolepis have 

 short, swollen, obtusely pointed crowns, like the back teeth of some 

 existing Crocodilia, and they sometimes exhibit signs of wear by 

 mutual attrition. 



In the pectoral arch, the scapula resembles that of recent Croco- 

 diles ; but the coracoid is short and rounded, like that of the Orni- 

 thoscelida, and of some existing Lizards, such as Hatteria. 



As in existing Crocodiles, there is an interclavicle, but no 

 clavicles. 



. The humerus is more Lacertian than that of existing Crocodiles 

 in the expansion of its ends, and the presence of a ridge and groove 

 on the radial side of its distal end. 



The ilium differs from that of existing Crocodiles and is more 

 Lacertian, in the large size of the ala, especially in front, and in the 

 forward prolongation of its anterior dorsal angle ; further, in the 

 shape of the ventral margin of the acetabular portion of the bone, 

 and in the absence of any notch or excavation in that margin. 



The acetabular end of the ischium resembles that of a Lizard, and 

 not that of a Crocodile ; and the rest of the bone is shorter dorso- 

 ventrally, and longer antero-posteriorly, than in recent Crocodiles, in 

 both which respects it closely resembles Belodon. The distal end of 

 the femur is narrower in proportion to its proximal end and to the 

 distal end of the humerus than in recent Crocodiles. 



Among known forms of Keptilia, the nearest ally of Stagonolepis 



