1913.] NATURAL SCIENCES OF PHILADELPHIA. 657 



Estimated alt. 30, actual alt. 25.5, diameter 14.75, length of 

 aperture 11.5, width of aperture 7.75 m:m. 



Two specimens of this species were taken at Tucmiare on the Rio. 

 Jamauchim. The sculpture is of the type of the D. transversa group, 

 being somewhat similar to that of D. inconspicua, but the shell is- 

 very much more obese than any member of that group. 



Genus HEMISINUS Swainson. 

 Hemisinus brasiliensis (Moricand). 



Melanopsis brasiliensis Moric, Mem. de la Soc. <,Le Phvs. et d'Hist. Xat. 

 de Geneve, VIII, p. 144, pi. .3, figs. 12, 13 (1837). 



About fifty specimens come from Alcobaga on the left l)ank of the 

 lower Tocantins. 

 Hemisinus flammeus n. sp. PI. XXV, fig. 15. 



Shell ovate conic, rather heavy; epidermis rather light, slightly 

 shining; color yellow-olive, marked with long, black flames, generally 

 rather narrower than the intervening light spaces; growth lines 

 showing distinctly, and everywhere marked by rather shallow, 

 distant spiral sulci, obsolete above in some specimens, and becoming 

 more defined and closer on the base. Apex lost in all specimens,, 

 remaining whorls 2j to 4, scarcely convex, indistinctly shouldered 

 below the sutures, subangulate below the periphery of the last whorL 

 Aperture oblique, narrowly elliptical, very acutely angled above, 

 bluish-white within except where the external flammules show 

 through; outer lip thin, sharp, rather evenly curved to an angle with 

 the produced, truncate base; parietal Avail without callus, the 

 epidermis and external sculpture extending within the aperture 

 beyond the lein of vision; columella slightly concave above, nearly 

 straight and vertical below, obliquely truncate at the base; anterior 

 canal well marked. Type with 3 whorls, alt. 23.5, diam. 11.5, length 

 of aperture 13, width of aperture 6.5 mm. 



Most mature specimen with 2^ whorls, alt. 22, diam. 12 mm. 

 Six specimens of this species, come from the Rio Jamauchim. It is 

 smaller and rather more slender than H. zebra Rve., which it resembles 

 in color pattern and seems to be more closely related to H. venezue- 

 lensis Rve. and H. bicinctus Rve., but differs radically from both of 

 them in color pattern and somewhat in general contour and shape 

 of whorls. 

 Hemisinus flammeus elongatus n. sub&p. PI. XXV, fig. lf>. 



Two specimens taken in the Rio Jamauchim, at a different date 

 and possibly at a different location from the preceding, dift"er from 



