264 Transactions. — Zoology. 



My collection contains specimens from Nelson, three locali- 

 ties near Wellington, Wanganui, Hastwell's, and Biverhead 

 (near Auckland), the latter being from brackish water, and 

 small. 



Type in the British Museum. 



Potamopyrgus badia, Gould, sp. 



Amnicola badia, Gould, Proc. Bost. Soc. Nat. Hist., vol. iii. 

 (1848), p. 75 ; U.S. Expl. Exp., vol. xii. (1852), p. 126, fig. 150. 

 Hydrobia fischeri, Dunker, Mai. Blatter, vol. viii. (1862), 

 p. 152. Hydrobia reevei, Frauenfeld, Verh. Zool. Bot. Gesell. 

 Wien, vol. xiii., p. 1024. Hydrobia fischeri, badia, reevei, 

 v. Martens, Crit. List. N.Z. Moll, pp. 14, 15. Bythinella 

 fischeri, badia, reevei, Hutton, Manual N.Z. Moll. (1880), p. 82. 

 Potamopyrgus corolla, Hutton, Trans. N.Z. Inst., vol. xiv. 

 (1882). p. 145, pi. i., figs. B, F (not of Gould). Potamopyrgus 

 corolla, Hedley and Suter, P.L.S. N.S.W. (2), vol. viii. (1893), 

 p. 619 (not of Gould). Potamopyrgus corolla, Suter, Journ. 

 de Conch., vol. xli. (1893), p. 619 (not of Gould). 



The type of this species is not spiny, the whorls moderately 

 convex, shouldered above, and the dimensions given are : 

 Length, | in. = 5 mm. ; breadth, T ^ in. = 2 mm. ; ratio of B : L 

 = 1:2-5.° 



This is the species that since 1882 was erroneously called 

 corolla by New ^Zealand conchologists. I have specimens from 

 the River Avon which perfectly agree with the description and 

 measurement given by Gould. Some are spinous, some shouldered 

 and without spines, and others have smooth, flatishly rounded 

 whorls. These typical specimens are, according to my experience, 

 very rare, and it is curious that this form, instead of the very 

 common one, should have been collected. The common form 

 has the following dimensions — length, 5 mm. ; breadth, 2|— 3 mm. 

 — having thus a somewhat greater angle of the spine. Both forms 

 were found living together in the River Avon. 



I know this species from the South Island only, and the finest 

 specimens I found in the Rivers Avon and Heathcote, near 

 Christchurch. Specimens from Akaroa have smooth, rounded 

 whorls ; a globose form, also smooth, and measuring 4J x 3 mm., 

 comes from Kowai Bush. Similar smooth forms are in my col- 

 lection from Mount Somers, Bealey, Birch Hill (Tasman Valley), 

 and Opawa, near Albury, the latter agreeing with H. fischeri. 

 From the Leith, Dunedin, smooth and spinous forms are mixed, 

 but the former are more abundant. I mentioned the occurrence 

 of a large form of P. cumingiana from Lake Te Anau in these 

 Transactions (vol. xxvi., p. 121), measuring 8x4 mm. Careful 



