42 MR. OLTtriBLD THOMAS OTSr THE [Teb. 5, 



18. Mus NOKVEGicns Erxl. 



(^Mus decumanus Pall., auctorum.) ^ 

 Common in all the towns. It has also taken to an aquatic life 

 in many places, and is the "Water-rat" of the workers in the 

 Albufera of Majorca. 



19. Mus EATTTJS ALEXANDEINUS GreofEr. 



a-b. San Cristobal, Minorca. 



" Common in all the islands '' (Barcelo). 



This Eat was living a wild natural life, away from houses, among 

 the trees on the hill-sides, and is probably perfectly indigenous in 

 the islands. Unlike M. spicilegus, however, it also occurs in the 

 houses, wherever it has not been ousted by the more powerful 

 M. decumanus. In colour it is a fulvous grey above and white below, 

 as unlike the typical Black Eat as could well be conceived. 



20. Mus SYLVATICUS L. 



a-7)t. Inca, Majorca. 



n-o. San Cristobal, Minorca. 



As is the case everywhere else in Europe, the Long-tailed Fleld- 

 Mice are the commonest and most easily trapped of the Balearic 

 mammals. They are of rather large size, running about 99 to 

 105 mm. in length of head and body, and are on the whole rather 

 dark in colour, very few of them being rufous. In this respect 

 the Majorca specimens are remarkably uniform, all being of a 

 dark greyish colour, but the Minorca ones are more variable. 



21. Mrs MuscuLus L. 

 Common, as usual, everywhere, 



22. Mus SPICILEGUS Pet. 

 a-f. Inca, Majorca. 



g-m. San Cristobal, Minorca. 



This is the Mouse which, under the name of a " wild-living form 

 of the Mus^ muscidus group," I recorded some years ago ^ as occurring 

 at Ciutra in Portugal. Further observation shows that it is quite 

 a distinct animal from the house-haunting Mus muscidus, and in 

 searching for a name applicable to it I find that the Hungarian 

 Mus spicilegus Petenyi is so closely allied to it that for the present 

 it would be inadvisable to separate the two. The Algerian Mus 

 spretus Lataste also belongs to the same group. 



The Balearic specimens are quite like those which I first caught 

 at Cintra, and show no sign of insular specialization. 



We also found this species at Cerbere, at the eastern end of 

 the Pyrenees, on the Franco-Spanish frontier, that being as yet 

 the most northern locality in the west of Europe where this form 



^ See Eehn, P. Biol. Soc. Wash. 1900, p. 167. 

 ■' Zoologist (3) XX. p. 137 (1896). 



