OF CONCHOLOGY. 219 



43. Unio pernodosus. Lea. Two specimens. It is apparently a 



good species. 



44. " perplexus, Lea. * 



45. " perradiatus, Lea. Retained in deference to Mr. 



Wheatlej. (See multiradiatus). 



46. " phaseolus^ Hildreth. 



47. " plentis, Lea. 



48. " propimpms, Lea. Abundant. 



49. " pudicus, Lea. The young shells appear to me to be 



pudicus ; the mature ones bear a strong resemblance 

 to U. Lyonii, Lea. My determination is question- 

 able 



50. " pustulosus, Lea. 



51. " Pybasii, Lea. Occurs also in small streams. 



52. " Ravenelianas, Lea. A single specimen. May not be 



correctly determined. 



53. " rectus, Lam. 



54. " securis, Lea, 



55. " sparsus. Lea A single well characterized specimen. 



56. " Steivardsonii, Lea. 



57. " sitbtentus, Say. 



58. " tenuissimus, Lea. 



59. " tesseruloe Lea. A single immature shell ; determina- 



tion questionable. 



60. " triangularis, Barnes. 



61. " tuherosus, Lea. Occurs in the Holston, Clinch and 



Tennessee Rivers with a more inflated form than is 

 seen in typical specimens. 



62. " undulatus, Barnes. 



63. " varicosus, Lea. 



64. " verrucosus, Barnes. 



65. Margaritana dehiscens, Say. Rare. 

 QQ. " marginata, Say. 



67. " rugosa, Bar. Rare. 



68. Anodonta ohlita ? Lea. A single small specimen. Deter- 



mination doubtful. 



Univalves, (in alphabetical order). 



69. Ajiculosa Cincinnatiensis, Lea. In presenting my opin- 

 ions on the species I am now considering, it may be well to pre- 

 mise that I began the study of the Strepomatidse of the Holston 

 River strongly impressed with the correctness of Mr. Tryon's 

 determinations and synonymy, and with a desire to profit by his 

 then unquestioned advantages. After a very thorough study of 

 an immense number of specimens, of different ages and varieties, 

 I arrived at results which are as follow : 



