60 CATALOGUE OF 



6. Pisidium pusillum (Gmelin) Jenyns. 

 [Pis. I, f . 8 ; III, f. 4 ; XXI.] 



1791. ? Tellina pusilla : Graelin in Linn4, Syst. Nat. 13th ed , i, p. 3231, 



no. 16. 

 1822. Cyclas pusilla [pars] : Turton, Conch. Brit. p. 251, pi. xi ; f. 16 & 17 ; 



id., Manual, 1831, p. 16, f. 7. 

 - Ct/cUis fontinalis, Lam, : Nilsson, Hist. Moll. Svecia?, p. 101. 



[Fide Malm, Gotheborgs K. Vet. & Vitt. Sarah. Ilandl. iii, 1855, 



p. 104.] 



1831. Cyclas f/ibba, Leach MS. : Alder, Trans. Nat.H.st. Soc. Northumbld. 



i, p. 41. (Cf. id. ii, 1838, p. 341.) 



1832. Pisidium pi/sillum, Gmel. : Jenyns, Trans. Carab. Phil. Soc. iv, 



p. 302, pi. xx, f. 4-6. 



1852. ? Euglesu hensloiciana, Leach, Moll. Brit. Pynop. p. 291. 



1854. Pisum pitsillum, Giuel. : Desliaves, Ca,t. Conch. Brit, Mus. ii, 

 p. 277. 



1853. Pisidium cazerttinum, var. y. thermale : Moquin-Tandon, Hist. Nat. 



Mull. France, ii, p. 584. 



1853. Musculium pusilluin, Gmel. : Adams, Gen. Kec. Moll, ii, p. 452. 

 1871. Pisidium milium, \nr.normandianitm, Dupuy : Clessin. Mulakozool. 



Blatt. xviii, p. 194. [Vide specimens from Clessin in Lindholm 



Coll.] 

 1899. Pisidium clessini, n. sp. [pars]: Surbeck, Rev. Suisse Zool. vi, 



p. 482, pi. xii, f. 6-15. 

 1903. Corneocyclas (s.s.) pusilla, Gmel.: Dtill, Proc.Biol.Soc. Washington, 



xvi, p. 7. 

 1908. Pisidimn tornense, \\. sp. : OJhner, Naturw. Uutersuch. Sarek- 



gebirges, iv, p. 154, pi. iii, f. 9-13. 



AVhat the Telluia pusilla of Gmeliu really was will now never 

 be known ; he describes it (97, i. p. 3231) as :- 



" T. testa oval a rentricoea, tenui transverse striata, cardine 

 in altera valva edentulo, in altera dente primario duplici." 



He applies the name to a shell described in Schrb'tcr's "Geschichte 

 dcr Flussconchylien" (160, p. 194) as " C'harna fluviatilis trans- 

 versim striata subovata." The crude figure that accompanies this 

 description (160, pi. iv, f. 7 & b) represents a very strongly-striato 

 shell that might be Pisidium pulcJieUum, but the shape of which 

 suggests a young P. amnicum. Lister, Turton and others applied 

 the name to the smaller forms of the genus without adequate 

 discrimination and cannot be quoted. 



Jenyns, however, having adopted and applied the name to a well- 

 deiiiifd form, his selection must be adhered to. His diagnosis (83, 

 p. 303) is: 



" Testa variabilis, plerumque orbiculabo-ovalis, interdum 

 suboblonga margine dorsali recto, vix ina3quilateralis ; praa- 

 ccdenti [P. obtusale] multo magis compressa, marginibtu 

 acutis; saepius extrauea rubigineobtecta, qua remota, apparent 



