plesiosaurid^:. 145 



44602. An entire right humerus or femur, agreeing very closely 

 with the preceding ; from Swindon. 



Presented by the Directors of the Swindon 

 Brick and Tile Company, 1873. 



Pliosaumis ferox (Sauvage 2 ). 



Syn. Liopleurodon ferox, Sauvage 2 . 

 Polyptychodon ferox, Sauvage 3 . 

 ? Pliosaurus pachydirus, Seeley 4 . 

 ? Thaumatosaurus mosquensis, Kiprijanoff 5 . 



Usually about equal in size to the type species. Teeth with the 

 carinaa imperfectly developed and approximated, and, in some cases, 

 ridges developed on the intercarpal space. Vertebrae of the general 

 type of those of P. macromerus. A mandible from the Oxford Clay 

 of Peterborough in the Collection of Mr. Leeds has 28 teeth and a 

 length of 3 ft. 6 inches. 



This species (the type of Liopleurodon) was founded upon teeth 

 from the Oxford Clay of Boulogne. Similar teeth occur in the same 

 formation in England, and it is probable that the cervical vertebras 

 from the Oxford Clay to which the name P. pachydirus was applied 

 are specifically the same. The same remark will apply to the 

 Russian Thaumatosaurus mosquensis of the Oxfordian. 



This species was probably the ancestor of P. macromerus. 



Hab. Europe (Prance, England, and (?) Russia). *' 



R. 1279. A tooth, wanting the greater part of the root ; from the 

 Oxford Clay (Middle Jurassic) near Peterborough, North- 

 amptonshire. This specimen, although of rather smaller 

 dimensions, agrees precisely with the type tooth figured 

 by Sauvage in the ' Bull. Soc. Geol. France,' ser. 3, vol. i. 

 pi. vii. fig. 1. There is a small and distinct intercarinal 

 space, and the ridges on the concave surface are approxi- 

 mated. It would accord well with the large teeth figured 

 by Kiprijanoff in the ' Mem. Ac. Imp. St. Petersbourg,' 

 vol. xxxi. art. G, pi. xii., as Thaumatosaurus mosquensis. 

 Presented l>y A. N. Leeds, Esq., 1888. 



R. 1279 a. Cast of the crown and upper part of the root of a much 

 larger tooth. The original was obtained from the "Oxford 



1 Bull. Soc. Geol. France, ser. 3, vol. i. p. 378 (1873). — Liopleurodon. 



2 Loc. cit. 



3 Bull. Soc. Geol. France, ser, 3, vol. viii. p. 544 (1880). 



4 Index to Aves &c. in Cambridge Museum, p. 118 (18(59). — Undescribed. 



5 Mem. Ac. Imp. St. Petersbourg, vol. xxxi. art. 6, p. 27 (1883). 

 PART II. L 



