APODEMUS 



837 



but m 2 with no minuto anterior cusp on outer side,- and m l and 

 m., without cingulum-like outer ledge. 



External characters. — The general external form is less slender 

 and delicate than in the members of the Apodemus sylvaticus 

 group, the ear is shorter, reaching barely to eye, though not 

 peculiar in structure, the feet are more robust, and the tail is 

 relatively shorter and more coarsely annulated. Palms as in 

 A. sylvaticus, except that the two intermediate tubercles are 

 relatively smaller. Feet with metatarsal portion relatively 

 shorter than in A. sylvaticus, but toes showing no peculiarities. 

 Plantar tubercles rather small, very sharply denned, the postero- 

 external minute and sometimes obsolete ; space between tubercles 

 rugose, though rather less so than in A. sylvaticus. Caudal 

 annulations very distinct, about fourteen to the centimeter at 

 middle ; caudal hairs essentially as in A. sylvaticus but less 

 abundant, the pencil ill-defined. Mamma; : p 2 — 2, i 2 — 2 = 8. 



Colour. — Upper parts a reddish brown between the russet 

 and wood-brown of Ridgway, brighter posteriorly, more dull 

 anteriorly, fading nearly to ochraceous-buff on sides and cheeks ; 

 ears and face between eyes and muzzzle noticeably tinged with 

 hair-brown ; a clear black median stripe about 3 mm. wide 

 extends from region just behind eyes to within about 10 mm. of 

 base of tail ; underparts and inner surface of legs dull white 

 clouded by the slaty undercolour ; tail not bicolor, the general 

 effect hair-brown somewhat darker above than below ; feet vary- 

 ing from pale drab to dull whitish. The 

 young are essentially like the adults, differ- 

 ing only in a slight general dulness of 

 colour. 



Skull. — In general appearance the skull 

 resembles that of Apodemus sylvaticus, but 

 the brain-case is longer and narrower and 

 the rostrum is shorter and more noticeably 

 tapering. Profiles essentially as in the 

 related species, but occiput more obliquely 

 truncate, so that a greater portion of the 

 supraoccipital is visible when skull is viewed 

 from above. Interparietal with antero- 

 posterior diameter as in A. sylvaticus, but 

 with lateral extremities abruptly and 

 almost squarely truncate at region where 

 bone has width of about 1 • 5 mm., thus con- 

 siderably reducing transverse diameter ; pos- 

 terior border of interparietal lying along lambdoid suture, the outer 

 anterior angles of the bone therefore encroaching on parietals.* 

 Margins of interorbital region conspicuously beaded, the raised 



* In Mus musculus, which has a similarly ligulate interparietal, the 

 lambdoid suture passes along the anterior border of the bone, so that the 

 parietals are not emarginated (fig. 177, p. 866). 



Fig. 168. 



Apodemus agrarvus. 



Nat. size. 



