128 Royal Society. 



regards as identical with the Belemnite, many examples of the body 

 with eight uncinated arms, and a pair of long tentacula, having an 

 ink-bag and pallial fins, have been discovered. The osselet of this 

 animal, like that of the Belemnite, has a fibro-radiated structure, 

 investing a conical chambered shell ; but this organ, for reasons 

 fully detailed in the memoir, the author considers could never have 

 been contained within the alveolus of a Belemnite ; the soft parts 

 of the animal of the Belemnite are therefore wholly unknown. 



Many beautiful specimens of Belemnites and Belemnoteuthis were 

 exhibited by Dr. Mantell to the Society, in proof of the statements 

 contained in the memoir. 



2. " On the Pelorosaurus ; an undescribed gigantic terrestrial 

 reptile, whose remains are associated with those of the Iguanodon 

 and other Saurians, in the Strata of Tilgate Forest." By Gideon 

 Algernon Mantell, Esq., LL.D., F.R.S., Vice-President of the Geo- 

 logical Society, &Co 



The author had for a long while entertained the idea, that among 

 the remains of colossal reptiles obtained from the Wealden strata, 

 there were indications of several genera of terrestrial saurians, 

 besides those established by himself and other geologists. The re- 

 cent discovery of an enormous arm- bone, or humerus, of an unde- 

 scribed reptile of the crocodilian type, in a quarry of Tilgate Forest 

 in Sussex, where Dr. Mantell had many years since collected nume- 

 rous teeth and bones of the Iguanodon, Hylseosaurus, &c., and some 

 remarkable vertebrae not referable to known genera, induced him to 

 embody in the present communication the facts which his late re- 

 searches have brought to light 



The humerus above-mentioned was found imbedded in sandstone, 

 by Mr. Peter Fuller of Lewes, at about 20 feet below the surface ; 

 it presents the usual mineralized condition of the fossil bones from 

 the arenaceous strata of the Wealden. It is four and a half feet in 

 length, and the circumference of its distal extremity is 32 inches ! It 

 has a medullary cavity 3 inches in diameter, which at once separates it 

 from the Cetiosaurus and other supposed marine saurians, while its 

 form and proportions distinguish it from the humerus of the Igua- 

 nodon, Hylaeosaurus, and Megalosaurus. It approaches most nearly 

 to the Crocodilians, but possesses characters distinct from any known 

 fossil genus. Its size is stupendous, far surpassing that of the cor- 

 responding bone even of the gigantic Iguanodon ; and the name of 

 Pelorosaurus (from TreXwp pelor, monster) is therefore proposed 

 for the genus, with the specific term Conybeari, in honour of the 

 palseontological labours of the Dean of Llandaff". 



No bones have been found in such contiguity with this humerus, 

 as to render it certain that they belonged to the same gigantic rep- 

 tile ; but several very large caudal vertebrae of peculiar characters, 

 collected from the same quarry, are probably referable to the Pelo- 

 rosaurus; these, together with some distal caudals which belong to 

 tiie same type, are figured and described by the author. 



Certain femora and other bones from the oolite of Oxfordshire, 

 in the collection of the Dean of Westminster, at Oxford, are men- 



