656 PROCEEDINGS OF THE ACADEMY OF [DeC, 



more distinct spiral strife over the whole shell ; periphery of the last 

 whorl sharply angulate. Remaining whorls of the largest specimen 

 (type) 4^, with probably two or three postnepionic whorls wanting, 

 nearly flat; sutures lightly impressed. Aperture oblique, elongate 

 pyriform; outer lip thin, simple, joining the parietal wall at an acute 

 angle, straight for over half its length, then curving sharply into the 

 produced basal lip; columella concave, smooth, scarcely revolute, 

 subangulate at its junction with the basal lip; parietal wall with a 

 thin, brown callus overlying, but not completely obscuring the epi- 

 dermis and basal sculpture where it extends well within the aperture. 



Alt. 19.5, diam. 8.5, length of aperture 7.75 mm. 



This species is distinguished from D. hohenackeri Phil, of Surinam, 

 by its smaller size, conic form, and absence of axial folds. 



Three specimens come from the Rio Jary and sixteen specimens 

 from near St. Antonio da Cachceira, "in a side arm of the Rio Jary 

 full of rapids." 

 Doryssa cachoeirae sulcata n. subsp. PI. XXV, fig. 10. 



Three specimens taken in the Rio Jary with three of the type 

 specimens differ from the type by being less sharply angulate at the 

 periphery of the last whorl and by being sculptured throughout the 

 whole shell with a continuation of the low spiral cords found only 

 on the base of the type. The whorls of the subspecies are also less 

 positively flattened than those of the type. 

 Doryssa tucunareensis n. sp. PI. XXV, figs. 11, 12. 



Shell of moderate weight, ovate conic, with nearly straight sides, 

 covered by a thin epidermis; color yellowish-brown to chestnut and 

 marked by small, sparsely scattered black spots which are generally 

 irregularly placed, but may form axial rows; everywhere marked by 

 low-rounded, distinct, but not prominent, nearly equal spiral cords, 

 five to a whorl, with six or seven on the base, the intervening spaces 

 rather sharply incised and narrower than the cords; about twenty 

 vertical to slightly protractive and arcuate axial ribs present on the 

 early whorls, never very prominent, and becoming obsolete on the 

 last whorl and base; growth lines very prominent over the whole 

 shell. Apex eroded, remaining whorls 4, very slightly convex and 

 indistinctly shouldered above ; sutures scarcely impressed. Aperture 

 markedly oblique, broad ovate, whitish within except where the 

 external maculae show through; outer and lower lips sharp and 

 slightly crenulated by the external sculpture, base effuse; columella 

 very convex, rounding into the parietal wall which is covered by a 

 well-marked callus with a distinct posterior canal. 



