1902.] MR. R. LYDEKKER ON AN ELK FROM SIBERIA. 107 



foi'm from the Norwich Crag and East Runton (text-fig. 13, 

 no. 7), which has characters of its own ; (3) Mr. Newton's name 

 intermedms is I'estrictecl to the form or forms met with at West 

 Runton (text-figs. 13, no. 1 ; 14, nos. 11-13; 15, nos. 21, 22, 25, 

 26) and a few from East Runton (text-fig. 15, no. 24). I am, 

 however, quite convinced that at least double this number of 

 species ought to be recognized, and am only prevented from doing 

 so at present because I do not wish to found species on isolated 

 teeth. 



The larger Crag species is mainly characterized by the presence 

 of tlie enamel islet, except in quite old specimens ; by the earlier 

 development of fangs ; by the presence of an enamel islet in the 

 last upper molar also ; and by the presence of three roots in the two 

 anterior upper molars, whereas in M. intermedms these same 

 teeth have only two roots. 



The four anterior lower molars of M. intermedms^ in which the 

 islet occurs, are all very little worn, although full-grown. It is 

 therefore probable that the enamel islet will be found to be a 

 constant feature in the young teeth of M. intermedii(,s, but more 

 ephemeral than in M. plioccenicics. I propose to form a distinct 

 genus, Mimomys, for all these Yoles with rooted molars, which 

 are clearly different from Uotomys, Phenacomys, and Dolomys. 

 M. neiotoni may prove, hereafter, to form a distinct geniis. 



In the Savin Collection there are, besides those already referred 

 to, about 17 fragmentary jaws and a small number of isolated 

 teeth of Microtus, provided with rootless teeth throughout life ; 

 with one exception, a, single anterior lower molar tooth from East 

 Runton, they all came from the West Runton Upper Freshwater 

 Beds. There are at least four difierent forms ; several of them 

 show in the conformation of their lower anterior molar some 

 resemblance to such living forms as M. arvalis (text-fig. 15, no. 27), 

 M. nivalis (text-fig. 15, no. 19), and M. gregaUs (text-fig. 15, no. 18). 

 On closer inspection I find, however, that, with the single exception 

 of one isolated tooth, I can refer none of these remains to any 

 recent nor to any hitherto known fossil species. The majority of 

 the rami, ten in number, have nothing to do with the subgenus 

 Microtus, but show in their anterior lower molar a feature (text- 

 fig. 15, no. 28) which is characteristic of the European and some 

 of the American members of Pitymys, and is found almost 

 identical in tlie North- American Pedomys, 



Mr. Lydeldcer exhibited the skull and antlers (text-fig. 16, 

 p. 108) of an adult male Elk from Siberia, together with the 

 antlers of a second example, lent by Mr. Rowland Ward. 



The skull indicated an animal of at least 6 or 7 years old, 

 the cranial sutures being for the most part obliterated, while the 

 cheek-teeth were about half- worn. It was that of a somewhat older 

 animal than the one to which an American skeleton mounted in 

 the British Museum belonged. In the latter the palmation of the 



