148 OXYSTYLA, SOTTI! AMERK AX. 



the first one black-tipped, nearly planorboid, the earlier two or three 

 smooth except for short low folds just above the suture, the following 

 whorls moderately convex. 



Aperture somewhat oblique, rather small, purple-tinted, white in- 

 side; peristome simple, broadly bordered with purple-brown inside 

 and out, columella subvertical, rather long, slightly convex, or some- 

 what calloused, white or dark chestnut colored ; parietal callus 

 chestnut. 



Alt. 62, diam. 30, longest axis of aperture 27^ mill, (specimen). 



Alt. 85, diam. 40 mill. (Crosse). 



-6a?/'S of the Amazon (Reeve); Upper Amazon (Orton); Mission 

 of Sarayacn, Pern (Castelnau); Napo, Ecuador (Martinez). 



Bnlimus (Orthalicus) adan>soni(Gray), BECK, Index, p. 60 (1837). 

 Helix (Cochlitoma) regina var. ft minor, FERUSSAC Tabl. p. 49; 

 Ilistoire, pi. 119, f. 1, 2. iJtilimus bensoni REEVE, Conch. Icon. pi. 

 78, f. 571 (Sept., 1849). PFH., Monogr. iii, p. 388; viii, p. 261 ; 

 Conchyl. Cab. p. 75, pi. 21, (. 1. HUTE in Castelnau's Exped., p. 

 31. Orthalicus bensoni SHUTTLEWOKTH, Notitia; Mai. p. 60, pi. 4, 



f. 3, 4, 5 CHENU, 111. Conch, i, p. 439, f. 3225 HIDALGO, Journ. 



de Conchyl. 1870, p. 64; Viaje al Pacifico, Mol., p. 133, pi. 7, f. 13. 

 CROSSE, Journ.de Conchyl. 1871, p. 318. Zebra bensoni MILLER, 

 Malak. Blatter xxv, p. 186 COUSIN, Bull. Soc. Zool. France xii, 

 p. 198.. 



The long spire with large, rather niainmillar apex, the three articu- 

 lated girdles, and the tine but strong decussation of the surface are 

 cliararteri-tic. There is a single variceal purple-brown streak on the 

 penultimate whorl of the specimen drawn in tig. 62; one of Shuttle- 

 worth's illustrations shows a similar stripe, and Ferussac's shell has 

 one. The pattern varies, some specimens having narrow, others 

 wide stripes, and the greenish-yellow cuticle of some shells is largely 

 wanting, or very thin and pale yellow below on other specimens, 

 otherwise in good condition. The large specimen from Napo (length 

 HU, noi s5 mill.), commented on by Hidalgo (fig. (55) has "a callos- 

 ity superimposed upon the, columella, as in <>. rnjinit, and due \\ith- 

 out any doubt to advancing age." This group of Oxyttyltt certainly 

 approaches (\u-ou<t in the convex form of the columella. 



This species \vas noticed lir^t by Fenissac, who considered it a 

 -mall foi'iii of his //. rryina, and figured it on the plate of that spe- 

 cies. Beck, in 1837, gives the name "<>. ailamsoni (Gray) B." to 



