284 Remarks on Certain Species of 



Helix Dorfeuilliana Desk. Fer. Hist. I. p. 73, tab. 69 D. fig. 3. (cxcl. 



Syn.)- 



Texasiana Desk. 1. c. p. 74 (excl. desc. Syn. et fig.). 



fatigiata Binn. Terr. Moll. II. p. 193, ex parte (excl. Syn.) pi. 



xxxix. fig. 4. 1851. 



" Shuttl. Diag. n. Moll. p. 17 (Bern. Mittheil.). 1852. 



Polygyra " W. O. Binn. Reprint of Say's Descr. of Terr. Shells 



of N. Amer. p. 37. 1857. 



In order to appreciate correctly Say's species, his remarkably 

 lucid description and remarks should be carefully studied ; for 

 facility of reference I subjoin them: 



"Polygyra fatigiata. Shell convex beneath, nearly plane above, the 

 spire being hardly perceptibly elevated ; whorls a little over six, com- 

 pressed, acutely carinated, crossed by numerous raised, equidistant lines, 

 which form grooves between them ; superior surface not at all convex ; 

 aperture subreniform ; labrum reflected, regularly arcuated, describing 

 two-thirds of a circle ; within two toothed, lower tooth conic obtuse, 

 superior tooth compressed, transverse, placed further within the aper- 

 ture than the inner one, from which it is separated by a wide and deep 

 and obvious sinus ; labrum with a very profound duplicative ; which 

 has a concave surface, but with no emargination near its acute tip ; 

 beneath exhibiting only two volutions, without any distinct groove on 

 the external one near the suture ; beneath the carina the elevated lines 

 are obsolete. 



"Greatest breadth seven-twentieths of an inch. 



"Found by Mr. Lesueur in the vicinity of New Harmony. It is very 

 closely allied to that species which I described under the name of 

 plicata ; the character of the mouth is very similar, but in that shell, 

 such is the situation and form of the teeth of the labrum, that at first 

 view they do not seem to be separated by a remarkable sinus, and the 

 inferior tooth is compressed and larger than the other; the duplicature 

 of its labrum is emargiuate near the tip. The present species is also 

 larger, carinated, and the elevated lines are obsolete below the carina." 



No doubt can exist as to the form indicated by Say under 

 the above description, and it is strange that the species should 



