Catalogue of Land and Fresh Water Shells. 101 



39. Unio ovata, Say. 



L. 4, H. 3. Like No. 48, but abruptly flattened posteriorly 

 on each side of hinge. 



40. Unio parva, Barn. 



L. H. Dull gray, 



41. Unio perplexa, Lea. 



L. 2^, H. 1^. Like No. 22 but irregularly noduled — on 

 anterior side of sulcus. Female broader and flatter and 

 rounder on posterior part. 



42. Unio personata, Say. 



L. \ l /2, H. \y 2 or more. Shell thick, slight sulcus, finely 

 rayed with dark green lines. 



43. Unio phaseola, Hild. 



L. 3^, H. 1^. Compressed. Yellow. Interrupted rays of 

 blue. 



44. Unio pilea, Lea. 



Male of No. 42. 



45. Unio plena, Lea. 



L. 2, H. 2. Like No. 37 but higher and thicker through the 

 beaks, nacre pink. 



46. Unio plicata, Lea. 



L. 3^, H. 2^. Like No. 35 but very slightly plicate. 



47. Unio pustulata, Lea. 



Like No. 48 only two rows of pustules. 



48. Unia pustulosa, Lea. 



Like No. 17 but fewer pustules and irregularly grouped nearer 

 the lower margin. 



49. Unio pyramidata, Lea. 



L. 2^, H. 4. Like No. 45 but grows much larger. 



50. Unio rangiana, Lea. 



L. 2)4, H. \y 2 . Like No. 41 but sulcus and surface of shell 

 smoother. 



51. Unio recta, Lam. 



L. 5 or more, H. 1 7-8. Black, faintly rayed; nacre some- 

 times partly purple. 



