[.ate Pltistocene VuU/t and Ltmmxtigs 35 



and Soutliern Europe*. It is illstinj^iii.sliocl from tlie liviii;^ 

 nuMiiln-rs of the latter group not only by its more liighly 

 Bpccialiiscd ocjipital region, but by the greater specialization 

 of the pterygoid region and its larger siz<>. ^o far as is 

 known, the speeies is confined to the latest portion of the 

 Pleistocene period in Hiitaiu, and h;i3 hitherto only been 

 found in the deposits of the I^hthani Fissures. 



Mivi'otus corneri, sp. n., fo33. 



Type. — An adult skull in thecolh-ction of Dr. Frank Corner 

 from the I^^htham Fissures (Late Pleistocene). 



VharacUrs. — iSkuU essentially as in M. orcadensis and its 

 nllies ; nasals and maxillary tooth-row a little shorter, 

 diasteme a Utile longer proportionally than in any of the 

 living members of the group ; inci-ors a little straighter and 

 more protruding than in J/, orcadensis \ upper surface of 

 superior ranjus of maxillary root of zygoma thickened, fusi- 

 form expansion of maxilla and jugal more extensive than 

 in M. orcadensis and sandoyensis ; interparietal shorter in 

 proportion to width than in adult ^f. orcadensis, the adult 

 Af. Corneri presenting the interparietal form of young 

 M. orcadensis ; brain-case differing from that of M. orca- 

 densis in being somewhat narrower and more depressed, from 

 M. sandayensis in being considerably narrower, and from 

 that of M. sarnius in being proportionally broader. Taking 

 the distance from interorbital constriction to lambdoid crest 

 as 100, the breadth of the brain-case at front edge of squa- 

 mosal root of zygoma amounts to 



95 in J/, sniid lyensis ive.strce. Type, B. M. 



1)3 in M. S'lndiiyensis. B. M. 6. 11. 18. 9. 



90 in M. orcadensis. B. M. 5. 12. 13. 2. 



><ii in .1/. corntri. Type. 



78 in J/. sarniu!<. B. M. J , 8. 9. 2. 27. Type. 



The constricted interorbital region is shorter than in 

 3/. orcadensis, almost exactly as in M. sandayensis ; molar 

 teeth of normal arvalis pattern, very light. 



Measurements. — Type skull: condylo-basal length 28'8 mm.; 

 zygomatic breadth 1G"5 ; interorbital constriction 3'G; occi- 

 pital breadth 13*0; occipital depth (median) 7"0; nasal 7*9; 

 diasteme 9'1 ; maxillary tooth-row 6'2. 



Si>(ciminn examintd. — One perfect and more than a dozen 

 fragmentary skulls, ijicluding one example from the Lang- 

 with Cave, Derbyshire ; the others from the Ightham 

 Fissures. 



• Miller, Proc. Biol. Soc. of Washington, 1910, March, pp. 19-22. 



