A Second Species of Planorbis from New Zealand. By H. J. Finlay, D.Sc. and C. R. Laws, M.Sc. [Issued separately, 23rd May, 1931.] The discovery of another species of Planorbis in New Zealand is of more than usual interest. Since P. corinna Gray was described in 1850, it has been accepted that there is only one species here, rather widely spread in the North Island, and recorded by Suter also from the River Avon and Lake Wakatipu. We can now announce, however, that there is a second species, apparently restricted to the Hawke's Bay district, differing at sight from corinna in its coiling. Early in 1927, some fresh-water molluses were forwarded to one of us (Finlay) for determination by Mr. C. S. M. Hopkirk, B.V.Sc., Officer in Charge of the Wallaceville Veterinary Laboratory. The species were rather important, for it was suspected that one of them acted as host for the notorious liver-fluke of sheep. This proved in the end to be Potamopyrgus zelandiae Gray, and Mr. Hopkirk has recorded this in the N.Z. Journal of Agriculture, vol. 35, No. 3, pp. 175–177; Sept. 20, 1927. He has also shown (l.c., pp. 141–150) that the path opened up by the fluke in the sheep's body also allows the entry, establishment, and rapidly fatal spread of the gas gangrene gacillus, B. oedematiens. Thus the extermination of fluke carriers in the district becomes a matter of importance. Amongst the fresh-water shells sent down were several specimens of a Planorbis which at once appeared distinct from corinna, no examples of which occurred. On being informed of the interest of his discovery, Mr. Hopkirk searched diligently for more specimens, and sent down a full range from adult to juvenile, though he stated that the draining of the swamps then in progress was making this species increasingly rare. We are perhaps fortunate to have received it before it was exterminated. It may be described as follows. Planorbis kahuica n. sp. (Text-Figs. 1, 2, 3). Shell very similar to P. corinna, but more rapidly expanding. No sculpture beyond fine oblique growth lines. Colour dark greenish-brown, whitish in places, hardly shining; some are light greenish-horn, and this is probably the true colour, the dark layer being a fresh-water deposit. Spire relatively more sunken than in corinna. Protoconeh indistinct, but apparently larger and less regularly globular than in corinna. Whorls three (corinna has nearly four—or perhaps more), more convex than in that species, especially the inner ones, and increasing in width more rapidly; each whorl is twice the width of its predecessor at the same spot, but only one and a third times in corinna; this makes the two species reach about the same size in the end, in spite of the difference of a whorl. Suture deeper, sub-canaliculate, bordered by a distinct narrow flat space before the convexity of the whorl begins (this is absent in corinna). Base much less