Royal Society, 61 



that our knowledge of the organization of the animal of the Belem- 

 nite is at present limited to the following parts, viz. — 



1. An external Capsule or periostracum which invested the osse- 

 let or sepiostaire, and extending upwards, constituted the external 

 sheath of the receptacle. 



2. The Osselet, characterized by its fibrous radiated structure, 

 terminating distally in a solid rostrum or guard, having an alveolus, 

 or conical hollow, to receive the apical portion of the chambered 

 phragmocone ; and expanding proximally into a thin cup, which 

 became confluent with the capsule, and formed the receptacle for 

 the viscera. 



3. The Phragmocone, or chambered, siphunculated, internal shell ; 

 the apex of which occupied the alveolus of the guard, and the upper 

 part constituted a capacious chamber, from the basilar margin of 

 which proceeded two long, flat, testaceous processes. 



These structures comprise all that are at present known of the 

 animal to which the fossi) commonly called " The Belemnite" 

 belonged. 



Of the Belemnoteuthis, the fossil cephalopod which Prof. Owen 

 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. Mantel! 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 Mantel], Esq., LL.D., F.R.S., Vice-President of the Geo- 

 logical Society, &c, 



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 



