698 



ME. J. W. HTJLKE ON 



the lower end of the pubo-ischial suture is 50 centim. An oval fora- 

 men, 6*0 and 6*5 centim. in its two diameters, pierces the bone at a 

 spot not far from the acetabular and ischiatic borders, and 31 centim. 

 distant from its anterior border. 



The ischium is a much narrower, less expanded bone than the 

 pubis. Its long axis appears as if twisted, the outer surface in the 

 upper part looking outwards and in the lower part of its extent 

 having also a backward inclination. Its length is 91 centim., the 

 breadth at its upper end, taken between the posterior angle of its 

 iliac suture and the lowest point of its pubic suture, is 35 centim. 

 Below this the figure rapidly contracts, so that at the middle of the 

 bone the width is only 15*5 centim., and this continues till towards 

 the lower end, where it enlarges to 17 centim. 



The resemblances which these remains — I refer particularly to the 

 pelvic bones — present to those of the Wealden Ornithojpsis are so 

 obvious as not to admit of any doubt respecting the very near 

 affinity of these two Dinosaurs, if, indeed, they are not actually 

 identical. The chief differences observable, the much larger size 

 and the massiveness of the Kimmeridgian form, are of a kind which 

 may merely express the greater age of this individual, and they do 

 not indicate generic distinctness. Pending, therefore, the acquisition 

 of new materials which, permiting the extension of the comparison 

 to other parts of the skeleton, will furnish a decisive solution of the 

 question of affinity or identity, it appears to me preferable to include 

 the Kimmeridge Dinosaur in the genus Ornitlwpsis than to make 

 a new genus for it. I propose for it the specific name Leedsii, 

 in recognition of the liberality with which Mr. A. Leeds affords 

 to scientific inquirers the opportunity of studying his valuable 

 collection ; and I am happy to express here my personal obliga- 

 tion to him and Mr. Ch. Leeds for much valuable assistance 

 kindly rendered in the course of my inquiry. 



In a former communication to this Society I expressed my con- 

 viction of the very near affinity of Cetiosaurus oxoniensis and Orni- 

 thopsis*. This was based chiefly on their vertebral resemblances ; 

 for the ischium and pubis of the latter were then unknown. But 

 the similarity is not less striking between their pelves, as will 

 become evident upon a comparison of the figure of the inferior pelvic 

 elements of Ornithojpsis in pi. xiv. vol. xxxviii. of the ' Quarterly 

 Journal' of our Society with the diagram at p. 277 in Phillips's 

 ' Geology of Oxford ' (London, 1871) ; only, because the bones are 

 represented misplaced, each figure in this diagram must be 

 turned over, the margins of the pubis and ischium in proximity 

 to which the measurements 1, 2 occur should be removed from these 

 numerals, and the roughened borders near the word " ilium " should 

 be joined vertically below the letter "a." "When this very excus- 

 able error has been rectified, the resemblances of the two pairs of 

 pelvic elements are very significant. 



* Quart, Journ. Geol. Soc. vol. xxviii. p. 36, vol. xxxv. p. 757, vol. xxxviii. 

 p. 374. 



