On a new Three-toed Jerboa from China. 279 submargiiiul cell is very long and narrow, and the marginal cell appears to be open, as in all Pseudosiricidae. Length of wing as preserved 45 rain., probable total length at least 50 mm. Basal nervure falling just short of transverso-medial ; lower section of basal nervure arched, 5 mm. long, forming nearly a right angle with the upper section, as in Formicium, the upper section 2 mm. long ; first discoidal cell 5 mm. long ; second 5*5 mm. on upper side and 8 on lower; second sub-marginal cell about 6 mm. long and hardly 2 mm. wide; marginal cell about 2*4 mm. wide (deep), the marginal nervure (radial sector) perfectly straight. The cubital nervure diverges from the marginal, so that 10 mm. beyond end of second submarginal cell they are 4'3 mm. apart. Bagshot Beds, Bournemouth [J. S. Gardner^. British Museum, I. 259G, with reverse. Related io Formicium,^ Qsiwoodi, from the Lower Purbeck at Durdlestone Bay. Handlirsch treats Formicium as a synonym of Pseudosirex^ but it is clearly a distinct genus. XXX YIL — A neio Three-toed Jerboa frotn China. By Arthur de Carle Sowerby, F.Z.S., F.R.G.S. In a collection of mammals presented by Mr. J. D. de La Touche to the British Museum are two specimens of a tliree-toed jerboa belonging to the genus Dipua, which were collected by Mr. A. L. Hall at Chili-feng \\\ North-eastern Chihli on or near the Mongolian border. They represent a form closely related to Dipus sowerbyi, originally described by Mr. Oldfield Thomas* from specimens collected by myself in the Yu-lin-fu district on the border of the Ordos Desert, some 500 miles to the south-west of Chih-feug ; but since they present diffe-rences in cranial and body measurements, as well as a slight variation in colour, and having regard to their geographical distribution, they may be considered as belonging to a distinct species, which, in view of the fact that lie was the original collector, I propose to name after ]\Ir. Hall : — Dipus hallif sp. n. In size this new species is somewhat larger than D. sow-erbyi, which in turn was described as being larger than • Auii. & Mag. Nat. Hist. ser. 8, vol. ii. (Sept. 1908).
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