42 SUPPLEMENT. 



A Pelorosaurus leedsi (Hulke *). 



Amej v ' 



yn. Ornithopsis leedsi, Hulke 2 . 



Of gigantic size, and only separable from P. humerocris- 

 tatus on account of its lower geological horizon. The pelvis so 

 closely resembles that of Brontosaurus (supra, i. p. 144, fig. 23) as 

 to show that the two forms were closely allied. 



The types were originally described as being from the Kimeridge 

 instead of the Oxford Clay, while the ventral aspect of the pubis and 

 ischium was mistaken for the dorsal 3 . 



R. 1716. Cast of the imperfect centrum of a lumbar vertebra. The 

 original was obtained from the Oxford Clay near Peter- 

 borough, in association with the type pelvis, and is pre- 

 served in the collection of A. N. Leeds, Esq., of Eyebury, 

 near that town. The portion of the body of the centrum 

 above the cavity is wanting, but the contour of the pos- 

 terior terminal face is fairly well preserved. The width 

 of the posterior face is about 0,292 (11*5 inches); the 

 length of the associated ischium being 0,897 (35*5 inches). 

 The corresponding dimensions of Brontosaurus eoccelsus are 

 0,354 (14 inches) and 1,012 (40 inches). The neural 

 arch belonging to the present specimen has the same 

 expanded spine as in Brontosaurus. Caudal vertebrae in 

 the collection of Mr. Leeds from the same deposits, which, 

 although not associated, doubtless belong to this species, 

 are indistinguishable from those of Brontosaurus. One of 

 them has a total height of 0,658 (26 inches), a width 

 across the centrum of 0,292 (11*5 inches), and a height 

 above the latter of 0,261 (10-3 inches) ; the corresponding 

 dimensions in Brontosaurus being 0,726 (28 inches), 0,305 

 (12 inches), and 0,267 (10*5 inches). The presence of 

 well-defined prezygapophyses and a single chevron-facet 

 as well as the expanded neural spine at once distinguishes 

 these vertebras from the caudals of Oetiosaurus. (See 

 table of measurements on p. 240 for comparative di- 

 mensions of the bones of this species.) 



Made in the Museum, 1889. 



** Bothriospondylus suffossus (supra, i. p. 170). 

 Incorrectly referred in Part I. to the Theropoda (see Introduction 

 to Pt. II. p. ix). 



1 Quart. Journ. Geol. Soc. vol. xliii. p. 695 (1887). — Omithojjsis 



2 Loc. cit. 3 Ibid. vol. xlv. p. 391. * 



