OF CONCHOLOGY. 223 



78. lo spinosa, Lea. 



- 79. lo turrita, Anth. Mr. Lea, in a letter relative to Jo, 

 expressed a doubt if there were more than one species of spinous 

 lo. I infer he would include all the spinous species under Jiuvi- 

 alis, Say. In this opinion I am disposed to coincide with him, 

 considering the varieties of Anculosa prcerosa, Say (which afford 

 a parallel), a good precedent. I observe in Miss Law's sheila 

 some peculiarities which I think have not been noted, lo bj-evis 

 has the first four whorls of perfect specimens smooth. lo spi- 

 nosa has tubercles on all the upper whorls. lo turrita has undu- 

 lations terminating in tubercles, on the upper whorls. I quote 

 from Miss Law's letters the following interesting remarks : " The 

 muscular power of lo is astonishing. I frequently find one 

 adhering to a rock half as large as my head, and when I take up 

 the shell it brings the rock with it, and requires much force to 

 separate it." lo is not confined to the Holston, as might be 

 inferred from the recorded statements of its habitat. Miss 

 Law has sent me specimens from the ClinQh River. Mr. Wheat- 

 ley has specimens from the Tennessee River. I have no doubt 

 it will also be found in the Little Tennessee River, and possibly 

 in other considerable streams that form part of the same system 

 of druinage. 



80. Melantho ponderosus, Say. I change the adjective ter- 

 mination for grammatical reasons. This species does not attain 

 as great size in the Holston, nor is it as abundant as in the Ten- 

 nessee River. 



81. Physa Saffordii, Lea. Possibly not correctly determined. 

 The shells collected by Miss Law are probably quite abundant. 



82. Somatogyrus Currierianus, Lea. I have from Miss Law 

 numerous shells identical with Somatogyrus jjarvulus, Tryon, 

 found, at very low stages of water, in little pools left by the 

 receding water along swift, shallow, gravelly portions of the 

 Holston. Less abundantly, a somewhat larger shell agreeing 

 with S. aureus, Tryon. Also larger shells identical with "^w- 

 nicola Currieriana, Lea," found in still water, along muddy 

 portions of the Holston, near the shore. They are, without 

 doubt, different ages of one species. Mr. Lea's name for the 

 species takes precedence. 



83. ^'■iStrephobasis Clarkii," Lea. Near Concord, somewhat 

 abundant. Varieties approximate ^'3fel. plena, Anth.,'' and sug- 

 gest a doubt whether S. Spillmanii, Lea, should be regarded as 

 a synonym o^ plena. I have a specimen of S. corj^ulenta, Anth., 

 to which the same remark will apply. 



