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Show 282 DR. EINAR LONNBERG ON HYBRID [Apr. 18, The foremost premolar of the maxillary is more simple in L . europceus, with, as a rule*, only two enamel-folds, while the same tooth in L. timidus has three. In this respect the hybrid resembles the latter species, as text-figure 53 shows. But the size of the teeth is, as also can be seen from the figure, larger than the average in the parental species. Text-fig. 53. A S c First premolar of the maxillary: A of L. europceus, C of L. timidus, and B of hybrid between both. (A and C 10 times enlarged, B 8 times enlarged.) This description appears to be sufficient not only to prove the presence in the hybrid of characteristics from both the parental species, but also to show that the hybrid is physically very strongly developed, even more so in certain respects than either of the parents. The masticating-power of the hybrid appears to have been especially greatly developed, with a grinding-surface larger than the average in the parental species. This has needed a greater development of the muscles moving this apparatus, and with the increase in size of the muscles the bones standing in relation to them have become altered, which indicates how easily even such characteristics as those derived from the skull may become altered (see text-fig. 54, p. 283). Two months later, when all the Hares, even in Scania, had assumed their winter garb, some more specimens were received from Count Thott. They all differed somewhat in colour. The two darkest had the fore-neck and breast, the colour extending even somewhat on the flanks, uniformly deep rusty red. The hairs of the upper parts were mostly black with broad subapical or apical bands of a rusty yellow. In these two specimens there were only very few traces of a lighter winter coat on the sides of the hind legs. The third was a little lighter and had a broad band above the tail on the lower back mixed with bluish grey. These three were no doubt true examples of Lepus europceus.-The fourth, however, seemed more than doubtful. It # Indications of the third fold may, however, sometimes be seen. |