582 Mr. M. A. C. Ilinton on 



character from those of this species, have been obtained from 

 the fissure-deposit of Tghtham, Kent, many British and Irisli 

 cavern-deposits of Late Pleistocene age, as well as from 

 several " submerged forests '^ and other Holocene accumula- 

 tions. No tolerably complete skull has, so far as I am aware, 

 been found hitherto, and, in the absence of such material, no 

 close comparison with any of the numerous forms of this 

 plastic species can be made. 



(b) Apodemus lewisi^ Newton. 



Mus abbotti, Newton, Quart. Journ. Geol. Soc. vol. 1. p. 195, pi. xi. 



tig. 8 (1894) ; not M. abbotti of Waterhouse. 

 Mus leioisi, Newton, P. Z. S. 1899, p. 381. 



Based on lower jaws and parts of skulls from tlie Late 

 Pleistocene fissure-deposit of Ightham, Kent. 



This is a large form wliich is closely related to, if it be not 

 identical with, A. fl.avicollis, Melchior. Mr. Newton states 

 that the anterior " accessory " cusp of ^^71 is very small or 

 wholly lacking. To this feature no great significance can be 

 given, because the cusp in question is frequently very small, 

 or, in slightly worn teeth, apparently absent in the recent 

 A.favicollis, as also in some races of A. sylvaticus. The 

 fossil material is very imperfect, and when fairly complete 

 skulls come to hand they may show differences from either 

 of the two western subspecies o\' jlavicoUis ; in the meantime, 

 it is better to maintain A. leicisi as a separate species than to 

 assert that it is identical with Jlavicollis. 



I have recently referred to A, lewisi specimens from three 

 other British Late Pleistocene deposits, viz. : — 



Kent's Cavern^ Torquay. — A right ramus (length 16'5 mm., 

 tooth-row 4*3 mm.) in tlie collection of Mr. Herron. This 

 was obtained from an upper stratum which yielded typical 

 Late Pleistocene rodents {Ockoiona, Microtus anglicus, rattu 

 ceps^ and Arvicola abbotti). 



Happaway Cave, Torquay. — Anterior part of a skull and 

 a left ramus (cheek-teeth 4*2 mm.) ; B.M. no. M. 580G 

 (Pengelly collection). 



Wye Cave, Gloucestershire. — Anterior part of a skull ; 

 B.M. no. 7789 (collected by Miss D. M. A. Bate). 



In both the Happaway and the Wye cave-skulls the teeth 

 are much worn ; the interorbital margins are sharp, the 

 superciliary ridges, particularly in the Wye specimen, being 

 sharply defined. The following dimensions show how 



