69 



its deep pits in longitudinal lines. The angle of the mandible is depressed. 

 The cotylus of articulation is partially concealed on the bulerside by the ele- 

 vation of the surangular, whose upper border is parallel with the inferior 

 margin of the ramus for two inches to where it is broken off. Tiic outer fiice 

 of this region is marked by irregular coarse ridges, more or less inosculating, 

 separated by deep pits. The lower posterior half of the angular bone is 

 smooth. 



A posterior dorsal or lumbar vertebra has a depressed cordate articular 

 cup. The zygapophyses are large and widely spread, and strengthened by 

 obtuse ridges running from the base of the neural spine to the posterior 

 margin of the anterior, and the posterior outer angle of the posterior. One 

 pit at basis of neural spine in front; two before. Ball prominent: sides of 



centrum concave. 



Measurements. 



ii. 



Lergth of a fragment of the ramus 0. lUO 



Width iufiout 0.034 



Depth Uchiud 0.0:52 



Length of tight alveoli — 0. 0(ii) 



Diameter of the largest alveolus 0.012 



Diameter of the smallest 0. 007 



Width of the base of the angle of the ramus 0.04a 



Depth at surangular 0. O^il 



Length of the centrum of the vertebra 0.045 



Width of the articular cup 0.031 



Vertical diameter of the articular cup 0.025 



Vertical diameter of the neural arch 0. Oil 



Expanse of the anterior zyg.apophyses 0. OiJG 



The specimen is adult, and indicates an animal about the size of the alli- 

 gator of the Southern States. Its reference to the present genus is provisional 

 only. 



SAUROPTERYGIA. — 



As compared with the European and New Zealand Cretaceous beds, 

 those of our country have yielded ])ut few remains of reptiles of this order. 

 Four only are embraced in the present work, three of which are from No. 3, 

 and one from No. 6. 



The structure of the scapular arch in Pulycotylus is yet unknown ; in 

 Elasmosaurus, it is quite distinct from that of Pleslosuurus, so much so as to 

 have induced me to regard it as type of a distinct family, the Elasmosauridce, 

 characterised by the absence of di.stinct mesosternal bone. Professor Seeley 

 has since more fully defined this group, and has discovered several species of 



