1890.] NATURAL SCIENCES OE I'lIIEADi:!,!'!! lA. 301 



ing in fi-ont. Aperture subtriiingular, ohlicjue ; peristome blunt, 

 not expanded, thickened within, with or without lip teeth ; parietal 

 wall bearing a stout, triangular, erect entering tooth. 



The species may stand as follows ; 



(1.) Peristome with two lip-teeth ; no denticles inside the body- 

 whorl. H. Harford iana. 



(2.) No lip-teeth ; body-whorl with several internal pairs of 

 denticles visible through the base. H. jjolygyrella. 



Dr. Cooper's ingenious supposition that the internal denticles 

 of H. polygyrella are "swallowed" lip teeth I find to be erroneous, 

 as they are formed quite a distance within the whorl, not at the 

 edge of the advancing lip. 



H. Harfordiana has been found only at the spot named above, 

 and only two specimens are known : that figured on the plate 

 accompanying this ])aper, and one other, a young shell, in the 

 collection of Dr. Cooper. 

 Goniobasis Crandalli. (PI. V, fig.s. 4, 6). 



Shell turreted, moderately tapering, truncated, with three and 

 one-half whorls remaining. These are very convex, separated 

 by deep sutures, and are more or less malleated (encircled by flat- 

 tened facets). The texture is exceptionally thin for a Melanian. 

 Color a very pleasing shade of olive-green, either unicolored or 

 having two chestnut bands, a narrow one above the periphery and 

 a wider on the base. The young ai'e much more conical, more 

 rapidly tapering than the adults, with an acuminate spire, and 

 when quite young the body-whorl is seen to be angulated at the cir- 

 cumference. The aperture is ovate, less than half but exceeding a 

 third the length of the whole shell ; the lip is a trifle sinuous. The 

 umbilical region is somewhat indented, and the inner lij) is folded 

 over upon it, very much as in Limncea. 



Alt. 122, diam. 6 mm.; alt. of aperture 5 mm., breadth 02 to 

 31 mm. 



Habitat, Mammoth Spring, Arkansas. 



A large number of shells have been examined by me, and com- 

 parisons made with all of the lengthened Gonlohases. The only 

 form really near in appearance is the western G. nigrina, which has 

 similar round whorls. Of the species occupying the same geographic 

 section, Professor Call's G. Ozarkensis is perhaps nearest ; but no one 

 could confuse specimens of the two, both young and adult shells 

 having a completely diverse facies. Of the latter species I have 



