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Show 1885.] MR. O. THOMAS ON THE RACES OF ECHIDNA. 331 Commencing with the external characters, the first thing to be noticed is the extraordinary difference between the Tasmanian and the northern races in the relative development of the spines and the hairs on the back. The extremes are indeed much further apart than one would ever expect to occur within the limits of a single species, but these extremes grade into each other on the examination of a large series. In the true E. aculeata of N e w South Wales we find that average specimens are covered with a thick coating of long stout spines, from 35 to 60 millim. in length, with a very sparse and thin undergrowth of hair, visible only upon separating the spines, and quite hidden in the ordinary position of the animal. The head, belly, and legs are covered with a mixture, in about equal proportions, of flattened semi-spinous bristles, and of thin, more or less woolly, hairs. Passing northwards, we find that in Queensland specimens (E. acanthion) the hairs of the back are still more reduced as compared to the spines, and that on the belly the flattened bristles tend entirely to supersede the hairs, a tendency carried out completely in E. lawesi, where, except in the neighbourhood of the pouch, the belly-hairs are entirely suppressed, and the head and underside are evenly though thinly covered with bristles only. On the other hand, probably owing to the moister climate of New Guinea, the hairs on the back somewhat reassert themselves at the expense of the spines, being in specimen a decidedly more visible than in average aculeata, and in 6 nearly as prominent as in setosa, the spines in both being reduced to from 20 to 35 millim. in length. Going now southwards from N e w South Wales, we find that the hair, as compared on the back with the spines, and on the belly with the bristles, rapidly gains the upper hand, until in Tasmanian specimens the spines, especially along the middle of the back, are almost entirely hidden, and the bristles below suppressed, both upper and under sides being clothed with thick woolly hair, some 20 millim. in length, a state of things obviously resulting from the moister and colder climate of Tasmania. There is also a good deal of variation in specimens from the same localities, probably owing to seasonal change; but as I have no dated specimens available, I am unable to speak definitely on this point. But as to the specific value of this hair-development, we soon find, on looking through a large series, that there are specimens which do not conform to the general rule as to locality; thus specimen/from South Queensland, the centre of the aculeata range, has its hairy covering developed almost precisely as in average Tasmanian individuals. Again, the fact that the New-Guinea Echidna, coming from a moist though hot climate, should tend to resemble the Tasmanian race in the length of the hair and shortness of the spines on the back, is alone strongly confirmatory of m y view that the greater or less development of the hairs is a character so directly climatic, and so easily affected in different localities by a greater or less degree of wet and cold, that it cannot be taken as indicating real specific distinction. The colour of the Echidna varies somewhat owing to the relative |