OCR Text |
Show 280 DR. EINAR LONNBERG ON HYBRID [Apr. 18, upper neck are white, but with the under-fur basally rusty yellow. The colour of the back is due chiefly to the longest hairs, which are dark brown with broad subapical rings of yellowish white. Nearly covered by these is a stratum of rust-coloured shorter hairs. The general colour of the upper parts of the body becomes through this arrangement greyish brown, lighter than the summer coat of Lepus timidus, but less rusty red than that of L. europceus. The under-fur is white, and on the sides the winter coat has developed so far that here and there cloudy spots of white are visible, and the lower parts of the flanks are clouded by white nearly all over. The shoulders could almost be termed yellowish white, the thighs ashy grey (" blue ") with intermixed dark hairs and a slight tinge of rusty. The under parts are white with a yellow stripe bordering the flanks. The fore legs and feet are light rust-coloured as in Lepus europceus, with white spots of the winter coat. The hind legs are as the thighs, only a little lighter, but the heel has a dark spot like the back. The hind feet are almost white on their upper surface, but some rust-coloured patches are left of the summer coat. The tail is white with a blackish-grey stripe above, better developed than in Lepus timidus but much less so than in L. europceus. The chest is light brownish grey with the white winter coat showing through. The belly and inner side of legs are white. The white " blue " winter coat is to be regarded as an inheritance from Lepus timidus, but it is evident that in the summer coat the head, neck, legs, and feet have had a colour that has agreed very well with that of L. europceus. Consequently it appears as if those parts which in summer are most like Lepus europazus in the winter become most like L. timiclus, which is a rather interesting fact. When skulls of these two species of Hares are compared with one another, the difference in the shape and size of the nasals is most conspicuous. Those of Lepus timidus are broader and shorter and form in the middle a rather broad, flattened area, from which the lateral parts are almost angularly bent and slope down towards the premaxillary. In X. europcxus the upper surface of each nasal is evenly convex, and this results in m a k in g ' the groove between the nasals in the median line deeper than in the former species. The upper and lateral parts are also less defined from each other in this species. The nasals in the hybrid are quite intermediate in shape. The convexity is less pronounced than in L,epus europceus, but the median groove is deeper than in L. timidus, and so on. The greatest width of both nasals is contained fully twice or more in the greatest length of the same bones in L. europceus, but, as a rule, this is not the case in L. timidus, with which the hybrid agrees in this respect. The zygomatic arches of L. timidus are more strongly developed and broader than in L. europceus. The shape of the anterior end |