Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/854

 $22 PROCEEDINGS OE THE GEOLOGICAL SOCIETY. [Julie 22, by Gegenbaur, — and conclude with the remark that this additional cnemial element, extending, as it does, the basis of support of the tarsus and digits, suggests the presence of additional postaxial digits above five, the number in the Liassic Plesiosauri. Should this prove so, it will add another and a striking resemblance to those already known between this subgenus of Plesiosaurus and the Plio- sauri and Ichthyosauri. I propose to distinguish this new Kimmeridge Plesiosaurus by the specific name of Manselii (Plesiosaurus Manselii). Dimensions of Centra of Vertebra?. Antero- posterior diameter. Transverse horizontal diameter. Vertical diameter. Distance between upper border of transverse pro- cess and level of upper surface of centrum. Cervical. No. 1 inches. •8 •8 1-8 2-2 2-5 2-4 2-2 22 1-9 1-6 1-0 inches. 1-2 1-3 1-7 21 40 4-4 42 4-3 3-6 2-7 1-4 inches. 1-2 10 1-7 2-5 3-2 3-4 3-6 34 30 2-2 1-5 inch. •8 ■7 1-3 1-8 1-9 2 6 12 27 Transitional ... Caudal. No. 1 6 12 16 ... EXPLANATION OF PLATE XLI. Figs. 1 to 6 illustrate the osteology of Plesiosaurus Manselii. Fig. 1. Ventral view of left humerus : a, proximal end ; b, distal end ; c, pre- axial border ; d, postaxial border. Proximal end of this humerus : a, articular caput ; b, trochanter. Ventral view of left femur : a, proximal end ; b, distal end ; c, pre- axial border ; d, postaxial border ; e, trochanter ; f, preaxial bone of leg ; g, first postaxial bone ; h, second postaxial bone. View of proximal end of this femur : a, articular head ; b, trochanter. Dorsal view of conjoined coracoids : a, front border ; b, posterior border ; c, c, glenoid fossae ; d, scapular facet. Fig. 6. View of outer end of coracoid : a, glenoid cavity ; b, scapular facet. Figs. 7, 8, 9. Vertebras of Plesiosaurus brachistospondylus. Fig. 7. Front view. Fig. 8. Back view. Fig. 9. Oblique view, showing the antero-posterior diameter or length of the centrum. Fig. 2. Fig. 3. Fig. 4. Fig. 5.