mus 875 



teristic of the large series of European specimens of Mus musculus 

 examined. Teeth as in Mus musculus. 



Measurements. — External measurements of type (adult 

 female) : head and body, 90; tail, 85; hind foot, 17-4; ear, 14. 

 Adult male and female from the type locality : head and body, 

 84 and 89; tail, 89 and 87 ; hind foot, 18-8 and 18; ear, 14 

 and 14. For cranial measurements see Table, p. 876. 



Specimens examined.— Fifteen, all from St. Kilda (B.M. and Edinburgh). 



9. St. Kilda, Scotland. G. Barrett-Hamilton (p). 8. 7. 16. 1. 

 (H. Evans.) (Type of species.) 



<?, 9 al. St. Kilda. J. E. Harting (p). 94. 7. 16. 2-3. 



1 al. St. Kilda. Kelvingrove Museum, 96. 0. 6. 1. 



Glasgow (p). 

 2 <5, 3 9. St. Kilda. W. Eagle Clarke (c & p). 11. 1. 24. 7-11. 



MUS MROENSIS Clarke. 



1904. Mus musculus fmroensis Clarke, Proc. Boy. Phys. Soc. Edinburgh, 



xvi, pt. ii, p. 163. Type in Boyal Scottish Museum. 

 1910. Mus musculus peroensis Trouessart, Faune Mamm. d'Europe, p. 146. 



Type locality. — Nolsoe, Faeroe Islands. 



Geographical distribution. — Faeroe Islands. 



Diagnosis. — Decidedly larger than Mus musculus and M. 

 muralis (hind foot, 19 to 20 mm., condylobasal length of skull, 

 23 to 23-4 mm.); hind foot very robust, its width at base of 

 outer toes about 5 mm. ; tail noticeably thickened, its diameter 

 near base about 4 mm. as opposed to 3 • 6 mm. in M. muralis and 

 about 3 mm. in M. musculus. 



External characters. — Except as already pointed out the 

 external characters agree with those of Mus musculus. 



Colour. — The few specimens examined indicate that the colour 

 does not differ essentially from that of Mus musculus. 



Skull and teeth. — The skull resembles that of Mus musculus 

 except for its larger size, relatively more robust rostrum and 

 apparently more depressed brain-case, though the material is 

 insufficient to show whether this last character is constant. In 

 the three skulls examined from Nolsoe the palate is as usual in 

 Mus musculus, the interpterygoid space broadly rounded or truncate 

 anteriorly, and the pterygoids, though imperfect, evidently not 

 far from parallel. The skull from Myggenses, however, as 

 pointed out by Dr. Wiwge in the letter published in the original 

 description of the species, has the pterygoid region exactly as in 

 Mus muralis. This skull (No. 1229 Copenhagen Museum) is 

 abnormal, the rostrum having been bent to the left, apparently 

 by some injury when the animal was young. The teeth are 

 slightly larger than those of Mus musculus, but I can detect no 

 peculiarities of form. 



Measurements. — Type (adult female) : hind foot (dry), 20. 

 Adult male from the type locality : head and body, 85 ; tail, 97 ; 



