AND AVES OF NORTH AMERICA. 



189 



meatal knob, and median posterior ridge both largo; a strong distal external ridge, 

 embracing with latter, an elevated rib, to the pit. ] Teeth. Medium, m. fulciatxjs. 

 aaa '{ Qviadratum ; caudals pentagonal; 

 Mandibular teeth twelve, spaced, (Owen); smaller. m. gracilis. 



IT. Centra of cervical, dorsal, and lumbar vertebra, transversely oval. 

 a Large species; the centra of posterior dorsals not keeled from di apophyses to the 

 cup. 



P An external alar angle from distal extremity to meatus; 

 Meatal pit within meatus; proximal articular face little curved, with long and narrow 

 branch on edge of convex ala. m. depressus. 



PP No ribs on the external face of the aria of the quadrate; 



Vertebra: but slightly transverse; quadrate with small alar and angular articular 

 surface; meatal pit external; knob very large, separated by a deep groove from very 

 prominent median posterior ridge; external distal longitudinal ridge rudimenta] or want- 

 ing; large. m. oartiirus. 



Mandibular teeth fourteen; pterygoid ten ; squamosal with broad triangular expan- 

 sion, above opisthotic. Quadrate bom; longer than broad. Dorsals transversely ovate, 

 sides rounded. M. MISSUIUENSIS. 



"-"■ Large species, the dorsals flattened, with lateral keel on side; 

 Diapophyses in front of middle of centrum; m. brumbyi. 



aaa Small species with depressed centra. 

 Centra- transversely ovate; caudals vertical ovate; M. MINOR. 



MOSASAURUS MAXIMUS, Cope. 



Proceed. Post. SOO. Nil!,. Hist, 1869, 862. 



A portion of an individual from the lower green sand bed of Monmouth Co., N. .1., has been submitted to 

 me by Hie Director of the Geological Survey of the State, Prof. Geo. 11. Cook. 



II, consists of a nearly perfect <>s quadratum, several dorsal and cervical vertebrae, including axis and atlas, 

 with numerous elements which lime been scattered and have not yet come into my hands. The remains indicate 

 an animal of Hie largest size. 



The quadrate bone compared with those of two other species from the New Jersey Green Sand presents marked 

 characters. Pour quadrate bones of the M. dekayi exhibit such constancy in the form, as was to have been antici 

 pated, while in the M. tnaximus and M. mitchillii, it is an obtuse angle and that over the ala a process, which is very 

 large in the former, and small in the latter. The knob just within the meatus of the ear is very prominent in the I/. 

 depresius and M. dekayi, while it is rudimenta] in M. maximum: in the latter the outer ridge bounding the meatus is 



■" MOSASAURUS OIGANTEUS, Soemmering. 

 Lacirta gigantea, Soemmering. Mosasaurae haffmanii, Mantell. M c<<v>iH:ri, Meyer. M. belgicu/t. Hall. 

 Upper cretaceous Belgium, Rhine Prussia ami England. 



MOSASAURUS GRACILIS, Own, 

 British Fossil Reptiles Tab. 



Uppar cretaceous England. 



AMERICA. PHILO. Sod. — VOL. XIV. 48 



