AND SAUROPTEKYGIANS OF THE PURBECK ETC. 49 



This, however, I cannot regard as anything more than a cliiFerence 

 in age or of individual development, seeing that both specimens are 

 apparently immature. 



The two posterior cervicals in the British Museum (Nos, 41238, 

 45904) are still smaller than Phillips's specimens, and have the de- 

 pression on either side of the haemal carina much less strongly marked, 

 this being partly due to their water-worn condition and partly also 

 to their immaturity. 



In describing those specimens in the Museum Catalogue, I con- 

 sidered that they would agree in relative size with the femur on 

 which Cimoliosauriis portlandkus was founded. A subsequent 

 opportunity of comparing the size of that limb with the entire 

 skeleton of Cimoliosaurus liicliardsoni has, however, convinced me 

 that the present specimens are more nearly of the size which 

 accords proportionately with the hind limb ; from which I also infer 

 that C. portlandicus was of the approximate size of the last-named 

 species. 



Hitherto, so far as I am aware, the only evidence of the occurrence 

 of a Sauropterygian in the Purbecks is afforded by an imperfect 

 humerus or femur mentioned on p. 227 of the above-mentioned 

 ' Catalogue.' It was then suggested that the specimen in question 

 might be referable to the "Wealden C. limnojDJiiliis, but it may equally 

 well belong to the present form. 



The freshwater vertebrates of the Purbecks, judging from the 

 Chelonia, appear to be closely allied to those of the Wealden, at 

 least one species •y}Ij/lceochehjslat:scutat't') being common to the two 

 series. It is therefore of considerable interest to find that where 

 marine conditions obtained there was an ecpially close alliance, if 

 we may judge from a single instance, with the vertebrate fauna of 

 the Portlandian. 



IV. A Pliosaurian Sic eleton from tlie Oxford Clay of Petcrhoroiujli. 



In a paper read before the Society on the21st of j^ovember, 1888, 

 I described under the name of Feloneustes * the remains of a com- 

 paratively small Pliosaurian from the Oxford Clay, which I n gaided 

 as a more generalized form than Fliosaurus, although it was doubt- 

 ful if it could be regarded as the direct ancestor of that genus. ^ly 

 reasons for separating Feloneustes from Fliosaurus were the great 

 length of the mandibular symphysis, the attachment of the neural 

 arches and cervical ribs by suture to the vertebra), and the relatively 

 longer epipodial bones, of which the ulna and fibula were subreniform. 

 I may add that in this description I considered that the pectoral 

 limb was larger than the pelvic ; but from specimens in the collec- 

 tion of Mr. Leeds it appears that the reverse condition obtains t, as 

 in Fliosaurus. 



* Quart. Journ. Geol. Soe. vol. xlv. pp. 48-r)r> (1889). 



t The liir.b fignrpd on p. 51 of (he memoir cited will actNM'dingly ho the 

 pelvic instead of the pectoral, as, indeed. T considered to be the c:i.*<e wlien the 

 figure was drawn. The tibia {t) is drawn too small in proporliou to the fibula 



(/)• 



Q.J.G. S. No. 181. E 



