Kto 



of J? en murk [Johansen (85, p. 9)1 ; in the Pleistocene (Carapinien) 

 of Conrtrai, Belgium [Mus. Hist. Nat. Brussels]; and in the 

 Pleistocene (Mosbacher Sand) of Mauer (near Heidelberg) [Geyer 

 (69, p. 96)]. 



11. Pisidium supinum, A. Schmidt. 



[Pis. IT, f. 5 ; IV, f. 7 ; XXV ; XXVI ; XXVII, f. 1 & 2.] 



Is.'O. Pisidium sitpinum, n. pp. : Schmidt, Zeitschr. f. Malakozool. vii, 



p. 119. 

 1^55. Pisidium jattdouinionun), nob. : Gassies, Actes Soc. Linn, Bordeaux, 



xx, p. 345, pi. ii, f. "2. 



Pisidium bonnafou.rianmn, P. de Cess. : Cessac, Bull. Soc. Sci. Nat. 



La Creuse, ii, p. 76. [For tig. see Baudon, Meiu. Soc. Acad. 

 Oise, iii, 1857, pi. iv, f. 1.] 



Pisidium henslowianum, Sliepp. [pars] : Malm, Gotheborgs K. 



Vet. & Vitt. Samh. Ilandl iii, p. 95. 



1856. Pisidium henslowianum, 8. bonnafourianum and f. jaudoniantim : 



Moquin-Tandon, Hist. Nat. Moll. France, ii, p. 581. 



1857. Pisidium conicum, nobis : Baudon, Mem. Soc. Acad. Oise, iii, 



p. 362, pi. v, figs. B, B, B, B. 

 18~>8. Musculium snpiuwn, Schmidt : Adams, Gen. Rec. Moll, ii, p. 4~>'2. 



- 1'ixnm supinum, Schmidt: ?W., torn. cit. p. ('60. 

 1866. ? Pisidium moitessierianum [n. sp.J: Paladilhe, Rev. et Mag. Zool. 



xviii, p. 172. 



1870. Pisidium henslowaniim, var. /3. supimim [sic], A. Schmidt: Kreg- 



linger, Syst. Verzeicli. Ueutsch. Biimen-Moll. p. 357. 



1871. Pisidium hensloicttnum, var. /3. normals [sic]: Westerlund, Nova 



Acta R. Acad. Sci. Upsala, in, viii, no. 1, p. 158. 

 1873. Pisidium baudonii, n. sp. : Clessin, Malakozool. Blatt. xx, p. 83, 



pi. iv, f. 1. 

 1890. Pisidium casertamim, vars. bonnafou.rianum & jaudouinianum 



[sic] : Westerlund, Fauna palaarc't. Region, vii, pp. 28 & 29. 

 1893. Pisidium trigonum, n. sp. : Bourguignat in Locard, Coquil. Eaux 



douces France, p. 148. 

 1903. Pisidium sujrinoide*, u. sp. : Clessin in Futterer, Durch Asieu, iii, 



p. 81. 



A very well-marked species, so that its quite recent recognition 

 in these Islands is remarkable. It vras tirst pointed out by Dr. A. 

 C. Johansen, who in 1901 found dead specimens in the muddy 

 foreshore of the Thames at low-water near Kew Gardens. It was 

 speedily detected first in the Lea Alluvium at Walthamstow (88, 

 p. 17 & 20) and then in most of the post-pliocene deposits of the 

 London district. Later a specimen that had been taken alive at 

 Eattersea was found in Dr. J. E. Gray's collection at the Natural 

 History Museum (1906. 6.18: 6-9) on a tablet with examples of 

 P. oblusale (1900. 6. 18 : 1-4) and labelled " Pera f/ibba " ; but it 

 was not until 1909, when specimens that had been taken by Mr. J. 

 E. Cooper in the Thames at Twickenham and Hampton Wick were 

 identified (44, p. 231), that it was definitely added to the British 

 Fauna. 



