BULIMULUS. 



389 



Fig. 271. 



B. alternatus (Say). 



in Mexico, as many specimens were sent me by Mr. Maclure ; but from what 

 particular locality I know not. (Say.) 



Bulimus alternatus, SAY, New Harmony Diss., Dec. 30, 



1830 ; Descr., 25; ed. BINNEY, 39. PFEIFFER, Mon. 



Hel. Viv., II. 221. W. G. BINNEY, Terr. Moll., IV. 



126, PL LXXX. Figs. 1, 3, 18 ; L. & Fr.-W. Sh., I. 200 



(1869). 

 Bulimus dealbatus, BINNEY, part, Terr. Moll., II. 276, PL 



LI. a, upper and lower fig., PL LI. b. Not SAY. 

 Bulimus Marine, ALBERS, Heliceen, 162. PFEIFFER, Proc. 



Zool. Soc., 1858, 23; Mon. Hel. Viv., III. 350; in 



CHEMNITZ, ed. 2, 157, PL XLVIII. Figs. 7, 8. W. G. 



BINNEY, Terr. Moll., IV. 128. 

 Bulimus Binncyanus, W. G. BINNEY, Terr. Moll., IV. 128. 



-Not PFEIFFER. 

 Thaumastus alternatus, TRYON, Am. Journ. Conch., III. 171, PL XIII. Fig. 16 



(1867). 

 Thaumastus Maria:, TRYON, Am. Journ. Conch., III. 172, PL XIV. (1867). 



Texan Subregion. From Louisiana through Texas into Mexico. It belongs 

 rather to the fauna of Mexico, extending into the Isthmus of Tehuantepec. 1 

 Found in great numbers upon bushes, the ground below them being often cov- 

 ered with dead shells. 



This species is readily distinguished from the allied forms by its greater 



solidity, its highly polished surface, its more 

 elongated form, its dark-colored aperture, bor- 

 dered with the white internal margin of the 

 peritreme, and the tooth-like callus upon the 

 upper portion of the columella. It varies con- 

 siderably in form, being sometimes quite slender, 

 at others quite globose. In color it shows every 

 variation from uniform brownish to pure white. 

 The aperture, however, is always dark, and has 

 a white, thickened rim within the peristome. It 

 is most attractive when ornamented with alter- 

 nate white and brown longitudinal blotches. 

 There can, I believe, be no doubt that the shell under consideration is what 

 Mr. Say described as allernatus. His description is given above, and a copy 

 (Fig. 271) of a colored drawing by Mrs. Say, under which is written, in Mr. 

 Say's hand, " Bulimus alternatus, Mexico, Wm. Maclure." 



The species was known to Dr. Binney and figured in the Terrestrial Mol- 

 lusks, but as a variety of B. dealbatus. Plate LI. b, and the upper and lower 

 figures of Plate LI. a, certainly represent the species. The central figures of 



Fig. 272. 



B. alternatus. 



Forbes (Proc. Zool. Soc., 1850, 54) mentions a Bulimus alternatus from Panama. 



