630 DR. FORSYTH MAJOR ON FOREST-BED MAMMALS. [Juiie 16, 



Dr. A. Smith Woodward, F.R.S., F.Z.S., exhibited photographs 

 and fragments of skin and bone of a Mammoth and a Rhinoceros 

 discovered in an ozokerite mine at iStarunia, Galicia. The 

 carcases of these animals appeared to have found their way into 

 an old marsh saturated with petroleum, which had completely 

 preserved them. The photogTaphs and specimens had been 

 received from Dr. George von Kaufmann, who intended to present 

 them to the British Museum. 



Jaiv of Canadian Beaver, loithfive lower cheeh-teeth. 

 Dr. 0. I. Forsyth Major, F.R.S., F.Z.S., exhibited, and made 

 the following remarks upon, the lower jaw of a young Canadian 

 Beaver (B.M. No. 55.3.11.4), in which there was present on each 

 side a small conical tooth antei'ior to the deciduous premolar 

 (text-fig. 131). 



Text-fie-. 131. 



A. :^2zmiri 



Molar teeth of riglit lower jaw o£ Castor canadensis. 

 A. Side view; B. Upper view of di and p^. p2= supernumerary premolar. 



" No Simplicidentata are known with normally more than four 

 lov^er cheek-teeth ; this holds good also with respect to the oldest- 

 known fossil Simplicidentata. We must, however, postulate still 

 older fossil predecessors with five lower cheek-teeth. As a transi- 

 tional stage between the latter condition and that exhibiting four 

 cheek-teeth. Rodents must have existed, probably in the Lower 

 Eocene, which had normally exactly such a diminutive anterior 

 tooth as is abnormally shown in the present specimen. I therefore 

 consider this supernumerary premolar to be a case of atavism." 



On species of Castor, fossil and recent. 



Drawings of some remains of two species of Castor from the 

 East Runton Forest-bed were also exhibited by Dr. Forsyth 

 Major. 



(1) Text-fig. 132 represents the four cheek-teeth from a right 

 mandibular ramus in the British Museum (M 7024), fr-om 

 Mr. Savin's collection. They are remarkable for the complex 

 and elegant plication of their enamel, whereby they agree with 

 the Beaver from the Upper Pliocene of the Yaldarno, Castor plici- 

 dens Maj., this specific name implying the principal and almost 



