280 BIVALVE SHELLS. 



10. PlSUM LENTICULARE. 



P. testa transverse ovata, compressa, inajquilaterali, antiee 

 producta, tenui, diaphana, subtilissime striata, albido-rufes- 

 cente ; umbone obtuso ; ligamento inconspicuo. 



Cyclas lenticularis, Normand, Noiice sur quelques CycZ.p.S.no.^. 

 f. 7, 8. 

 Hab. In fluvio Scaldise. 



11. PisuM Creplini. 



P. testa plus minusve ventricosa, orbiculato-rhomboidea, vel sub- 

 ovali, ina^quilaterali, antice producta, ])ostice brevi, tenui, pel- 

 lucente, concentrice atque tenerrime striata, unicolore lutea 

 seu albo-lutescente, seu zonis cinereo-nigricantibus et luteo- 

 olivaceis picta ; umbonibus obtusis, plus minusve tuberculosis, 

 antrorsum incurvis, approximatis ; hgamento minimo, fere in- 

 conspicuo, latere breviori insito ; dente bifido cardinali in 

 utraque valvula; laterales duo valde compressi. 



Cyclas Crepliui, Dunker, Zeitschr . filr Malac. 1845, p. 20. 



Hah. In fossulis paludosis prope Casselis loco Hottenkirchen 

 dicto. 



2. AfricancB. 



12. PlSUM PARASITICUM. B.M. 



P. testa ovato-transversa, convexduscula, inffiquilaterali, trans- 

 versim tenue et irregulariter striata, epidermide viridi-fusces- 

 cente vestita, atro-rubescente aliquantisper intus extusque 

 puncticulata ; latere antico brevi, obtuso, angusto ; postico 

 latiore extremitate obtuse truncato ; margine superiore recto, 

 inferiori parallelo ; cardine angustissimo, dentibus cardinahbus 

 obsoletis, lateralibus angustis, brevibus; umbonibus magnis, 

 obtusis, obliquis. 



Pisidium parasiticum, Parreys, MSS. 



Hab. In Nilo superiore. 



13. PlSUM LUMSTENIANUM. B.M. 



P. testa ovata, oblique trigona, tumida, insequilaterali, transversim 

 striata; natibus prominentibus, roseo-corneis. 



Pisidium Lumstenianum, Forbes, Moll. of Algeria, Ann. ofNat. 

 Hist. ser. 2. no. 10. 1838, p. 255. no. 45. pl. 12. f. 4. 



Hab. In fonticulis Mitidjanse. 



