200 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



ican alligator of 8 feet inches in length weighed 135 pounds, 

 while one of 2 feet 3 inches weighed only 2-J- pounds. 2 A, 

 December 17,1870,445. 



STRUCTURE OF MOSASAURUS. 



In the American Journal of Science for June, Professor O. 

 C. Marsh, of Yale College, has an article on some new fossil 

 reptiles discovered by the Yale party last summer in the 

 Rocky Mountain region. The cretaceous fossils described 

 are of great importance, as they prove conclusively that the 

 mosasauroid reptiles had a well-developed pelvic arch and 

 posterior limbs, although up to the present time no satisfac- 

 tory evidence of this had been discovered, and the eminent 

 palaeontologists who have recently made this group an espe- 

 cial study considered them probably destitute of these ap- 

 pendages. Some of the species discovered by Professor Marsh 

 were much more attenuated than any hitherto described. 

 One of them, which is named Clidastes wymani, was about 

 thirty feet in length, and had the terminal caudal vertebrae 

 less than one twelfth of an inch in transverse diameter. 



In the same paper are notices of several new species of ter- 

 tiary crocodiles from Wyoming, which were discovered in the 

 same ancient lake basin as the serpents and lizards already 

 described by Professor Marsh. 



NEW FOSSIL LAND LIZARDS. 



At a recent meeting of the Philadelphia Academy of Sci- 

 ences,Professor Marsh, of Yale College, described several new 

 species of fossil land lizards which were discovered in the ter- 

 tiary deposits of Wyoming by the Yale scientific party dur- 

 ing their explorations last summer in the Rocky Mountain 

 region. Some of these lizards were as large as any now liv- 

 ing in tropical America, but all were quite distinct from any 

 hitherto found. They represent a new genus, which was call- 

 ed Glyptosaurus, in allusion to the fact that the head and 

 parts of the body were covered with highly ornamented bony 

 plates. Four species were described, which are readily distin- 

 guished by the form and ornamentation of the shields on the 

 head. The largest of these, G. sylvestris, was about four feet 

 in length ; the smallest, 6r. anceps, apparently about two feet. 

 The other species were intermediate in size, and were called 



