M0SAS1UEIDJ3. 271 



R. 822. Mould of part of the skull K 

 R. 823. Block of matrix with vertebra. 

 R. 824. Matrix with ribs. 

 R. 825. Two pterygoid teeth. 

 R. 826. A vertebra. 



Platecarpus (?), sp. 



The undermentioned specimen is provisionally referred to this 

 genus. 



Bab. Europe (England). 



39424. The crown of a tooth; from the Chalk of Sussex. The 

 enamel is strongly grooved, and the specimen apparently 

 closely resembles the teeth of P. mudgei, figured by Cope 

 in the ' Eep. U.S. Geol. Surv. Terrs.' vol. ii. pi. xxvi. 



Bowerbanlc Collection. Purchased, 1865. 



Genus GEOSAURUS, Cuvier 2 . 



Syn. Halilimnosaurus, Ritgen 3 . 



Imperfectly known, but apparently very closely allied to Clidastes, 

 which may prove to be the same. 



Geosaixrus giganteus (Sommerring 4 ). 



Syn. Lacerta gigantea, Sommerring 5 . 

 Geosaurus soemmerringi, Cuvier 6 . 

 Halilimnosaurus crocodiloides, Ritgen 7 . 

 Mosasaurus bavaricus, Holl 8 . 



The type species. 



Hob. Europe (Germany). 



R. 1229. The middle portion of the skull, in a crushed condition 



(Fig.) from the Kimeridgian (Upper Jurassic) lithographic stone 



of Monheim, Pranconia. The type specimen. Figured 



by Sommerring in the ' Denkschr. k. Ak. Miinchen,' vol. vi. 



pi. accompanying memoir, figs. 1-7 ; and also by Cuvier 



1 This and the following specimens were determined by Dr. Hector, on whose 

 authority they are referred to this form. 



2 ' Ossemens Fossiles,' 2nd ed. vol. v. pt. 2, p. 338 (1824). 



3 Nova Acta Ac. Cres. Leop.-Car. vol. xiii. p. 331 (1826). 



4 Denkschr. k. Ak. Miinchen, vol. vi. p. 37 (1816 ; vol. dated 1820).— Lacerta. 



5 Loc. cit. 6 Loc. cit. 7 Loc. cit. 

 8 ' Handbuch der Petrefactenkunde,' pt. i. p. 85 (1829). 



