SOREX 33 



While there is no invariable rule, the colour in winter is 

 usually darker than in summer, and the tricolor pattern of 

 dark back, yellowish brown sides and greyish belly is more 

 pronounced. A trace of this pattern is often the most convenient 

 character by which to recognize shrunken ill-prepared specimens, 

 which might otherwise be mistaken for Sorex minutus. 



Skull. — The skull is slender and lightly built, with no special 

 peculiarities of form as compared with that of other shrews. 

 Brain-case well marked off from interorbital region, its surface 

 smooth except in extreme old age, its main sutures remaining 

 open until late in life. It is sub-circular in 

 general outline when viewed from above, 

 but with antero-external portion of border 

 noticeably flattened, so that at point of 

 greatest breadth there is usually an evident 

 angle ; condyles scarcely visible, causing no 

 break in posterior outline. Depth of brain- 

 case at middle slightly more than half 

 greatest width ; no sagittal crest except in 

 extreme old age ; lambdoid crest at first 

 confined to lateral portions of occiput, rarely 

 extending to median line. Dorsal profile 

 usually with evident concavity in inter- 



J . J . Sorex amneus. 



orbital region (more marked than in aorex Nat. size. 



minutus and S. alpinus). Nares broadly 

 rounded posteriorly, the lateral margin obtusely angled near 

 middle. Anteorbital foramen moderately large, not very con- 

 spicuous when skull is viewed from in front. Lachrymal 

 foramen over middle of to 1 . Mesopterygoid space nearly parallel- 

 sided, less than half as wide as long. 



Teeth. — Anterior upper incisor with basal lobe relatively 

 larger than in any other European shrew, the length of its 

 base nearly equal to diameter of anterior lobe at level of angle 

 between the two cusps. When tooth is viewed from below the 

 posterior lobe appears nearly as large as anterior cusp ; in 

 lateral view it approximates the size and form of first and 

 second unicuspid, and in height falls a little short of anterior 

 cusp. The two teeth come in contact anteriorly slightly below 

 tips, which do not diverge conspicuously. Anterior lower incisor 

 robust, its shaft very slightly tapering, its cutting edge with 

 three well-developed lobes, the lengths of bases of which 

 diminish regularly from first to third, the first lobe more 

 distinctly separated from succeeding lobe than from anterior 

 point of tooth. Upper unicuspids robust, their crowns squarish 

 in outline when viewed from below, bluntly triangular when 

 viewed from the side ; height about equal to length ; anterior 

 and posterior borders straight or faintly concave, upper border 

 convex, more strongly posteriorly than anteriorly. The highest 

 point of cusp lies slightly in front of middle of crown. Upper 



.D 



