W. C. Knight — New Jurassic Vertebrates. 115 



Art. XIII. — Some JVew Jurassic Vertebrates / by Wilbur 

 C. Knight. Paper No. III. 



For several years the Geological Department of the Uni- 

 versity of Wyoming has been directing its entire energy and 

 what little money it could procure toward building up a col- 

 lection of Jurassic vertebrates. On account of splendid suc- 

 cess in the field the collection has already assumed considerable 

 proportions and from time to time new animals are being dis- 

 covered. The bulk of the material at the present time is 

 Dinosaurus, but the marine beds of the Rocky mountain 

 Jurassic have not been neglected and a few marine reptiles 

 have been discovered. Among these are two new species of 

 the order of Sauropterygia, which belong to two genera, 

 neither of which have been reported from the Pocky mountain 

 Jurassic ; one of them being a Plesiosaur and the other a Cimo- 

 liosaur. With this addition to the fauna of the Eastern Pocky 

 mountain region, there are now known two species of Ichthyo- 

 saurs* and three species of the Plesiosaurf type. The two 

 skeletons which form the basis for this paper are not as com- 

 plete as one would like to have them for generic and specific 

 determinations, but there are sufficient remains in each case to 

 give a very good idea of the species. 



Plesiosaurus shirleyensis sp. nov. 



The remains of this species consists of vertebra from all 

 parts of the column ; there being many from the cervical 

 region ; numerous teeth and fragments of teeth ; a distorted 

 portion of the lower jaw and many phalanges. Teeth large 

 and numerous, incurved, elliptical in cross-section, interior sur- 

 face of the teeth covered with numerous very fine angular 

 stride, exterior surface nearly smooth and showing faint marks 

 of striae. The greater portion of one side of the lower jaw 

 measures -280 m in length and has a depth of - 035 m . The ver- 

 tebra are slightly biconcave, and all wider than long ; but in 

 the dorsals and posterior cervicals the length and breadth are 

 nearly equal. The neural spines were found attached to the 

 centra of the cervical vertebra, but the suture was obliterated. 

 On the anterior caudles the neural spines are of considerable 

 height. 



Nothing of importance is known of the dorsal vertebrae, 

 excepting that they are slightly biconcave and circular in 



* Baptanodon discus Marsh ; Baptanodon nateus Marsh. 



f Megalneusaurus rex Knight. See this Journal, vol. v, p. 378. 



