209 



NOTES ON SOME SPECIES OF PISIDIUM. 

 By B. B. Woodward, F.L.S. 



Bead 13th May, 1921. 



PisiDiUM ciNEEEUM, Alder, vice P. casertanum, Poli. 



When the " Catalogue of the British Species of Pisidium " was 

 issued in 1913, Poll's work ^ being binominal was accepted by most 

 zoologists, and had been included in Sherborn's " Index 

 Animalium ". Since there was no doubt as to the identity of his 

 Cardium casertanum., which, moreover, was the sole species in the 

 type locality, and the name had been in use on the Continent, it was 

 adopted in the "Catalogue." The fact, however, that Poli con- 

 sistently gave in each case one name to the shell and another to the 

 contained animal has since led to his book being ruled out as not a 

 serious contribution to systematic zoology, and his names have to 

 be discarded. 



What, then, will be the best name to replace casertanum, because 

 of those included in its synonymy some may, nevertheless, be open 

 to question when absolute certainty of identification is demanded. 



The next in order of date is the Cyclas vitrea of Risso,^ of which the 

 description is inadequate. Comm. E. Caziot most kindly sent me 

 plesiotypes of the specimens that are now in Risso's old collection 

 under the name, and these were certainly casertanum. There is, 

 however, grave doubt whether, considering the vicissitudes the 

 collection has been through,^ the present are the original specimens ; 

 certainly the name does not favour it. Risso could hardly have 

 described these shells as glassy. Hence it does not seem advisable 

 to accept his name. 



The Cyclas prisca of Eichwald,* which follows, was founded for 

 a fossil from a freshwater deposit at Kuncza, Podolia. The 

 description is worthless, and although Eichwald's figure ^ suggests 

 the present, or some closely allied species, until the type is known its 

 exact nature is uncertain, and the name best passed by. 



Of the Pisidium australe of Philippi,^ it can be stated that while 

 the description is better, it is still too general for purposes of exact 

 identification and the figure is poor and quite unidentifiable. 



^ Testacea utriusque Sicilise, etc. 



2 Hist. Nat. Eiirop. merid., iv, 1826, p. 338. 



3 Proc. Acad. Nat. Sci. Philad., 1919, p. 157. 



* Naturh. Skizze Lithauen, 1830, p. 207 ; and Lethsea Rossica, iii, 1852, 

 p. 87, pi. V, f. 8. 



* The figure given in illustration of this species by Hoernes, " Foss. Moll. 

 Tertiar-Beck. Wien," Abhandl. k.k. Geol. Reichsanst., iv, 1870, pi. xx, f. 1, 

 and repeated by Sandberger, " Land- and Siissw. -Conch. Vorwelt," 1875, 

 pi. XXX, f. 6, is quite a different shell. 



6 Enum. Moll. Sicil, i, 1836, p. 39, pi. xiv, f. 11. 



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