“I have in my collection two complete skins of the Addax obtained in South Tunis in the month of May, both of a milk-white hue, evidently the summer coat, the hair being very short and fine; while other skins in my possession obtained in February and March are of an isabelline dun-colour, and with the hair rather long and coarse, the winter garb, which no doubt varies in intensity of colour according to the season. The thick frontal tuft of hair seems to be of a dark brown colour at all seasons, while part of the face below the transversal white nose-band is a lightish brown, as is also the fringe of hair on the throat. On the nape there is a slight indication of a mane, but it is so slight in some specimens as to be scarcely noticeable. The tail is rather short and tufted. Both males and females carry beautifully-shaped spiral horns, those of the former being, as a rule, longer and stouter than those of the latter. The horns vary somewhat in the amount of spiral twist, probably according to age, as will be seen by two specimens of which the following are the measurements:— inches. inches. “Length along front curves 34½ 33½ Do. in straight line 27 27 Circumference at base 6½ 6½ Tip to tip 17½ 17 “I also send a photograph of the head of a female Addax, almost adult (see fig. 97, p. 85). “Since writing the foregoing I have received from South Tunis the complete skin and head of a fine male Addax obtained in the early part of this year (1898). The horns of this specimen are remarkably long, being in fact quite a record pair, and measure as much as 38½ inches along the front curves, and 30½ inches in a straight line. I have presented this specimen to the National Museum at South Kensington.” The Addax has likewise been the object of an expedition into the Sahara made by Mr. A. E. Pease, M.P., F.Z.S., who, in the Zoological Society’s ‘Proceedings’ for 1896, has given us the following account of his adventures in search of it:—