490 PYTHONOMORPIIA 



America. M. cctmpe7-i, from Belgium, with a skull about 4 feet 

 in length, armed with many large, curved, acrodont teeth. The 

 vertebral column consists of about one hundred caudal and thirty- 

 four precaudal vertebrae, of which seven are cervical, without 

 zygosphenes. The total length of the type-specimen is estimated 

 at 25 feet. 



Plaircarpus of North America and New Zealand, and various 

 other North American genera, also contained species of large 

 size. 



Lioclon. — Premaxilla without teeth, the others nearly smooth 

 instead of being ridged. With a very wide distribution in 

 the Chalk of Europe, North America, and New Zealand. L. 

 haumuriensis of New Zealand seems to have been the giant 

 amongst these monstrous marine creatures ; its total length has 

 been computed from imperfect fragments at 100 feet. 



Clidastes, of the Upper Cretaceous of North America and 

 Europe, although not so massive, comprises the most elongated 

 forms. The cervical vertebrae possess long median hypapophyses 

 with separate epiphyses ; most of the vertebrae are much 

 elongated and have well-developed zygosphenes. C. tortor had 

 a skull nearlv two feet and a half long. 



