106 Mr. Dawkins on the Dentition of Rhinoceros leptorliinus. [Apr. 26, 



either of the above formulse, as representing the composition of the most 

 explosive gun-cotton, and demonstrate satisfactorily that the material, pre- 

 pared strictly according to the system of manufacture perfected by Von Lenk, 

 consists uniformly of the substance now generally known as trinitro-cellu- 

 lose, in a nearly pure condition. 



IV. ^' On the Mysteries of Numbers alluded to by Fermat." By 

 the Et. Hon. Sir Frederick Pollock_, Lord Chief Baron, 

 F.R.S., &c. Received March 19, 1866. [See page 115.] 



April 26, 1866. 

 J. P. GASSIOT, Vice-President, in the Chair. 

 The following communications were read : — 

 I. On the Dentition of Rhinoceros leptorhinus (Owen).^^ By 

 W. Boyd Dawkins, M.A., Oxon.^ F.G.S. Communicated by 

 Prof. J. Phillips, F.R.S. Received March 28, 1866. 

 (Abstract.) 



The fossil remains of the genus Rhinoceros found in Pleistocene de- 

 posits in Great Britain indicate four well-defined species. Of these the 

 R. tichorhinus, or the common fossil species, ranged throughout France, 

 Germany, and Northern Russia, and, like its congener the Mammoth, was 

 defended from the intense winter cold by a thick clothing of hair and 

 wool. Its southern limit in the Europseo-Asiatic continent was a line 

 passing through the Pyrenees, the Alps, the northern shore of the Caspian, 

 and the Altai Mountains. It has not yet been proved to have existed in 

 Europe anterior to the deposit of the Boulder Clay. The second species, 

 the R. megarhinus of M. de Christol, characterized by its slender limbs 

 and the absence of the " cloison," has been determined by the author 

 among remains from the brick-earths occupying the lower part of the 

 Thames valley, and from the Preglacial forest-bed of Cromer. The species 

 ranged from the Norfolk shore southwards through Central France into 

 Italy. In France and Italy it characterizes the Pliocene deposits, being 

 found in the former country in association with Mastodon brevirostris and 

 Halitherium Serresii, in the latter with M. Arvernensis. From its 

 southern range we may infer that the megarhine species was fitted to in- 

 habit the warm and temperate zones of Europe, just as the tichorhine was 

 peculiarly fitted for the endurance of an Arctic winter. 



The third species is the R. etruscus of Dr. Falconer, confined to the 

 forest-bed of the Norfolk shore, and, like the R. megarhinus, found in the 

 Pliocenes of France and Italy ; it ranged across the Pyrenees as far as Ma- 

 laga, and is the only species known to occur in Spain. 



The fourth, the R. leptorhinus of Professor Owen, is the equivalent of 



