10 ICHTHTOPTEETGIA. 



R. 1307. Casts of the centra of an associated early cervical, anterior 

 or middle dorsal, and early caudal vertebra. The originals 

 of these specimens belong to an imperfect skeleton from 

 the Oxford Clay of Peterborough, Northamptonshire, in 

 the Collection of A. N. Leeds, Esq., of Eyebury, near 

 Peterborough. The dorsal is the 26th, and the caudal 

 the 47th of the series. The dimensions of the dorsal 

 are : — vertical diameter 0,082 (3*25 inches), transverse 

 0,039 (3-5 inches), length 0,035 (1-35 inches); and those 

 of the caudal: — vertical diameter 0,080 (3-2 inches), 

 transverse 0,078 (3-08 inches), length 0,027 (1-05 inches). 

 The cervical is pentagonal and much narrowed inferiorly, 

 and shows the cupping of the anterior face confined to the 

 central region. In the later cervicals of the same skeleton 

 the centrum becomes rounded inferiorly (as in fig. 7). 

 The dorsal has both faces completely cupped, and a peculiar 

 incurvation of the profile; in contour it appears indis- 

 tinguishable from the specimen figured by Phillips in his 

 'Geology of Oxford,' p. 338, diagram 130, figs. 1, 2, as 

 Ichthyosaurus thyreospondylus, but the relative length is 

 somewhat greater ; the dimensions of the later specimen 

 being, transverse diameter 0,070 (2*75 inches), length 

 0,025 (1*0 inch). The dimensions of the humerus associated 

 with the present specimens are : — length 0,145 (5'7 inches), 

 width at distal extremity 0,124 (4*9 inches). 



Made in the Museum, 1888. 



46491. An associated series of twelve vertebral centra, apparently 

 (Fig.) referable to this or a closely allied species ; from the 

 Kimeridge Clay of Eoxhangers, near Devizes, Wiltshire. 

 They comprise five posterior cervicals (one of which is 

 represented in fig. 7), an anterior or middle dorsal, five 

 later dorsals, and one posterior dorsal. The dorsals agree 

 precisely with the dorsal of No. R. 1307 ; and the pos- 

 terior dorsal narrows superiorly. In the cervicals (fig. 7) 

 the cupping of the anterior face is shallow and confined to 

 the middle area, and the contour of the inferior surface 

 is rounded. In the figured specimen the vertical dia- 

 meter is 0,066 and the transverse 0,074; the corre- 

 sponding dimensions in the first of the five contiguous 

 dorsals being 0,075 and 0,087. The upper costal facet 

 in the cervicals is partly on tbe arch and partly on the 

 centrum. Cunningtoh Collection. Purchased, 1875. 



