WEALDEN FORMATIONS. 37 



On referring to that volume and page, however, I find tlie description limited 

 to a partial quotation from my ' Report,' with the acknowledgment that " the four 

 huge caudal vertebrae already mentioned as assigned to the Cetiosaurus brevis, exhibit 

 very peculiar characters, fully detailed by Professor Owen." 



The only objection offered by Dr. Melville is to the " nomen triviale " of the 

 species to which they were assigned, and to which objection the reply has been given 

 above. The subsequent proposal to suppress the "nomen genericum " was made 

 under the following circumstances. In 1847 there was discovered, in the Wealden 

 of Tilgate Forest, Sussex, the limb-bone, measuring 4 feet 6 inches in length, 

 regarded as a " humerus " by Dr. Mantell, and, on account of its difference of 

 form from that bone in the Crocodiles, Iguanodon, and Hykeosaurus, and its large 

 medullary cavity, referred to a genus distinct from all then known Wealden Saurians 

 under the name of Pelorosaurus.* 



This unique fossil bone, of truly extraordinary size viewed as a humerus, was 

 obtained by purchase, for the British Museum, after the demise of Dr. Mantell ; 

 and with it a number of large vertebrse, most of them from the caudal region, 

 marked Pelorosaurus, were purchased at the same sale. 



These vertebrae, now bearing the Museum numbers 28.627, 28.633, 28.634, 

 28.635, 28.653, 28.654, 28.655, 28.656, 28.657, correspond in colour and mine- 

 ralized condition with the large, hollow long-bone. The original Mantellian labels, in 

 the same handwriting, ascribing them to Pelorosaurus, have been scrupulously 

 preserved, as they were attached to the specimens. It may, therefore, be inferred 

 that they belonged, in the opinion of Dr. Mantell, to the genus and species which he 

 established in the 'Philosophical Transactions' for 1850. Accordingly, the best 

 preserved of these vertebrae is here figured, of the natural size, in Tab. XI, as 

 the type of the anterior caudal vertebrae of Pelorosauriis, and the foregoing details 

 are given in support of this ascription ; because, singular as it may appear, not 

 any of the vertebrae, marked Pelorosaurus, and preserved by Mantell, with the 

 enormous limb-bone, in his private museum, as long as he lived, are figured, 

 described, or even alluded to in his memoir on that genus ; whilst he assigns to 

 the base of the tail of his Pelorosaurus, the four vertebrge which were obtained 

 by the British Museum, in the purchase of the first Mantellian Collection, in 1839, 

 which were entered as vertebrae of the Iguanodon in the catalogue then prepared 

 by the vendor, and on which I founded, in 1841, the species of Cetiosaurus, 

 distinguished as brevis, from the longer Cetiosaurian vertebrae of older Oolitic 

 strata. 



A glance at the vertebrae figured of the natural size, and from the same 



* rieXwp, monster, anvpos, lizard. 



