53 



b. The crown of a tooth ; from the bone-bed in the Lower Green- 

 sand, Upware, Cambridgeshire. Presented by Norman Moore, Esq. 



THAUMATOSAURUS CRAMPTONI. 

 Plesiosaurus cramptoni, Carte and Baily, Journ, R. Dubl. 

 Soc, vol., IV, p. 163 (1863). 



a. The entire skeleton, embedded in rock, with the dorsal aurfacG 

 exposed ; from the Upper Lias of Kettleness, near Whitby, York- 

 shire. Type. 



THA UMA TOSA UR US ARCUA TUS. 

 Plesiosaurus arcuatus, Owen, Rep. Brit. Assoc, for 1839, 

 p. 75 (1840). 



a. Slab showing the somewhat imperfect skeleton; from the 

 Lower Lias of Barrow, Leicestershire. The skull is seen from the 

 frontal aspect, and closely resembles that of T. cramptoni. A 

 considerable number of vertebrse are missing from the middle of 

 the neck. In the limbs only the humerus and femur are preserved ; 

 the femur being the larger, its length is 16. 5 and its distal width 

 7. 5 inches. 



THA UMA TOSA UR US MEGA CEP HAL US, 

 Plesiosaurus megacephalus, Stuichbury, Quart. Journ. Geol. 

 Soc, vol. II, p. 412 (1846), 



a. A number of slabs of rock containing the greater part of the 

 skeleton; from the Lower Lias of Street, Somersetshire. The 

 skull is entire, and larger than in T. megacephalus. The humerus 

 is, however, not larger than the femur, having a length of only 

 14 inches with a distal width of 8 inches. These differences in 

 the proportions of the limbs appear to confirm the specific dis- 

 tinction of this shorter-limbed form from T. arcuatus. One 

 coracoid is entire. 



b. A dorsal vertebra referable either to this genus or to one of 

 the larger species of Plesiosaurus ; from the Lower Lias ; locality 

 unknoMm. 



