Oeological Society. 93 



Mosasauridae as a family of Lacertilia equivalent to the Iguano- 

 dontidfe and Megalosauridae in the order Dinosauria. The order 

 Lacertilia among Reptiles, being equivalent to the order Caruivora 

 or Ferse among Mammals, the Mosasaurians would be the equi- 

 valents of the Seals in the latter. 



2. "Note on the Occurrence of the Remains of Hycpnarctos in the 

 Red Crag of Suffolk." By Prof. William Henry Plower, F.R.S., 

 F.G.S. 



The traces of Hi/cennrctos described by the author in this paper 

 consist of a right and a left first upper molar, which were obtained 

 from the Red Crag of Waldringfield, and are so much alike, that 

 but for the former being rather more worn they might have be- 

 longed to the same animal. On comparison these teeth were found 

 to show no appreciable difference from the corresponding teeth of the 

 original specimen of Hyct^narctos sivalensis from the Sewalik Hills, 

 and hence the author did not venture to regard them as represent- 

 ing a species distinct from the Indian one. The author discussed 

 the synonymy of this species, which was first described by Falconer 

 and Cautley, in 1836, under the name of Ursus sivalensis. The genus 

 Ayriotheriam was established for it by Wagner in 1837, and the 

 names Ampliiarctos and Sivalarctos were given to the genus by 

 Rlainville in 1841 ; but Falconer and Cautley's name Hycenarctos, 

 although certainly of later date, has been generally adopted. 

 Remains of the genus have been found in the Pliocene marine sands 

 of Montpellier {H. insignis, Gerv,), and in Miocene beds at Sansans 

 {H. hemiq/on) and at Alcoy, in Spain. A nearly perfect mandible 

 of U. sivalensis has recently been obtained in its original locality by 

 Mr. Theobald. 



3. " On the Remains of Hypsodon, Portheus, and Iclithyodectes 

 from British Cretaceous Strata, with Descrijjtions of new Species." 

 By E. TuUey Newton, Esq., F.G.S., of H.M. Geological Survey. 



Ilypsodon lewesiensis, as established by Agassiz in the " Poissoiis 

 Fossiles," it appears includes two forms which are generically 

 distinct, and the author felt justified in adopting Prof. Cope's sug- 

 gestion for their separation. It is proposed to retain the above 

 name for the specimen upon which the genus and species was rcallj- 

 founded, and to refer to the genus Portheus, Cope, the upper jaw, 

 with large irregular teeth, which had already been described by 

 Dr. ManteU in 1822 as " an unlinown fish." To this the specific 

 name of P. Mantellii is to be given. Another maxillary bono from 

 the Lower Chalk, characterized by its greater proportionate depth 

 and the convexity of its dentary border, as well as by the more 

 equal size of its teeth, it is proposed to name P. Daviesii. 



A very fine specimen from the Gault belonging to this same 

 genus was described in detail. This fish is closely allied to P. lestris. 

 Cope, but differs in the form of its maxilla and premaxilla, and is 

 chiefly remarkable for the peculiar incurving of the points of the 



