290 Remarks on Certain Species of 



Mr. Lea has kindly allowed me to examine his original spe- 

 cimen, which differs from mine only in having the parietal 

 tooth somewhat more emarginate. 



H. Troostiana is very closely allied to H. fatigiata Say, from 

 which I separate it with some hesitation. In its fresh state it 

 has a thin, sparingly hirsute epidermis. I have moreover two 

 specimens in my cabinet (both hirsute), which are as acutely 

 carinated as fatigiata, with the striae as prominent below as 

 above, — (in one more numerous), but both having the parietal 

 tooth of Troostiana. 



I am not altogether satisfied with the validity of Shuttle- 

 worth's remark, that the superior tooth in fatigiata is larger 

 and more conspicuous than in Troostiana. 



This species has the same tubercle within the last whorl as 

 H. fatigiata. 



The following are the measurements of my specimens, — of 

 one received from Judge Tappan, and agreeing with Mr. Lea's. 



Diam. maj. 8, min. 7, alt. 3. 



Var. b. — carinata. Diam. maj. 9, min. 8, alt. 3. 



Var. c. — minor. Carinate, and with striae below more nume- 

 rous than above — an additional one being intercalated between 

 nearly every pair passing over the carina. 



Diam. maj. 8, min. 7, alt. 3. 



Mr. W. G. Binney, in his "Notes on American Land Shells," 

 remarks on the plates in the " Terrestrial Mollusks" in the 

 following terms, — " Helix plicata Say. PI. xxxix. Fig. 2. 

 Mr. Say's type is preserved in the collection of the Academy. 

 Having carefully compared it with Mr. Lea's original Troosti- 

 ana, I am led to believe them identical. In this case Mr. 

 Lea's name alone will stalid, as that of Mr. Say is pre-occu- 

 pied." He adds, that of twenty-five specimens found in Ten- 

 nessee by Bishop Elliott, " all were well marked H. Troosti- 

 ana" Since our recent discussion of this subject, and further 

 careful study of the specimens referred to, Mr. Binney 



