examination, besides the figures referred to. Strange to say, we do not yet possess a single spoil' of this species in the museum of the Society! But I trust and have reason to believe that this singular hiatus in our series will speedily become a record of the past. Plate I, fig. 2, represents the broad type of skull of RH. SONDAICUS, from the Bengal Sundarbáns; and pl. II, f. 2, the same from the Tenasserim provinces. Pl. I, f. 3, and pl. II, f. 3, represent an aged specimen of the narrow type of SONDAICUS, from Jáva. We have Tenasserim examples quite similar, except that they are not so aged; but I figure the Jávanese one, that there should be no misapprehension about the identification of the species. I have already remarked that these comparatively broad and narrow types completely grade into each other, as likewise in the preceding species. It is simply impossible to trace a dividing line in the instance of either one of the three. Plate III, fs. 1, 2, represent the corresponding types of males of the two-horned RH. SUMATRANUS; f. 3, of a female, of which the stuffed skin of the head is also in the Society's museum. from the Tenasserim provinces. All are Plate IV, f. 1, is from a drawing which I took of a beautiful specimen in the possession of Lt.-Col. Fytche, Commissioner of the Martaban and Tenasserim provinces, at Moulmein.* The animal was killed in Tavoy province, near the frontier of Siam. When I first saw this specimen, the horns were attached to the skin; and they now fit to the rugosities of the bony surface. The resemblance of the anterior horn (more especially) to the extraordinarily fine horn figured as that of a new species, RH. CROSSII, Gray (in the Proc. Zool. Soc. 1845, p. 250, and copied in pl. IV, f. 4), induced me to conjecture that the latter was merely a magnificently developed specimen of the anterior horn of RH. SUMATRANUS; but the difference of size (that of RH. CROSSII measuring 2 ft. in span of curvature from base to tip) seems to be too great. Of the near affinity, however, there can be no doubt; and it is just such a horn as the nearly akin (however huge) RH. PLATYRHINUS of Cautley and Falconer, from the Siwâlik deposits, might have borne.† Other kindred fossil species * The horns, as represented in the lithograph, are not sufficiently massive. In a letter just received from Col. Fytche, who had recently returned from a tour in the southern Tenasserim provinces, that officer writes-"I came across |