1913.] NATURAL SCIENCES OF PHILADELPHIA. 649 



"Doryssa transversa (Lea). 



" Mdiinia transversa Lea, Proc. Zool. Soc. London, 1850, p. 186. 

 "Milania transversa Lea, Reeve, Conch. Icon., fig. 196a-c. 



"The typical form is a larger shell, with more spiral grooves than 

 the forms noticed below. Its exact location is unknown. 

 " Doryssa transversa jaryensis Pilsbry, n. subsp. PI. XXIV, figs. 1 to 7. 



"The shell is spirally grooved, five grooves on each whorl of the 

 spire, becoming weaker on the last whorl in most specimens. Minute 

 spiral lineolation is clearly developed. Axial sculpture of slightly 

 arcuate or nearly straight folds, which rarely persist as far as the 

 last whorl, usually being present on the spire or upper whorls only. 

 The whorls are nearly flat. Color Dresden-brown, Isabella color, 

 or honey-yellow, with small, irregularly^ scattered black spots, or 

 with numerous spots, more or less arranged in axial rows or confluent 

 into streaks which nearly cover the surface in some shells. Un- 

 cleaned shells are black from a coating of iron oxide. Apex truncate. 



"Length 30, diam. 12 mm.; 4^ whorls remaining. 

 " 32, " 11.25 " 6 



"Rio Jar}', St. Antonio da Cachoeira, in bed of river immediately 

 above the great falls. Twenty-four specimens. 



"Figs. 5, 6, 7 represent typical specimens. Fig. 3 is the most 

 strongly sculptured shell of the lot. Fig. 2 is not fully mature, 

 retaining more of the early whorls. 

 "Doryssa transversa tapajozensis Pilsbry, n. subsp. PI. XXIV, figs. 8, 9, 11, 12. 



"The shell tapers to a rather broad truncation in adult individuals. 

 Spiral grooves, five on each whorl of the spire, continuing on the 

 last whorl, and usually darker colored than the intervals, which are 

 of a dull citrine or olive-citrine shade. Microscopic lineolation weak 

 or subobsolete on the later whorls. Axial folds narrow, numerous, 

 typically well developed only on the earlier whorls, being weak, 

 irregular, or wanting on the later one to three whorls; sometimes, 

 however, continued to the last whorl. 



"Length 25, diam. 11.2 mm.; 4j whorls remaining. 

 " 23.7, " 11.5 " 3| " 



" 29, " 11.7 " 5 " " Roughly sculp- 



tured individual. 



"Rio Tapajoz, seven specimens. 



"While the form with obsolete axial sculpture and spiral dark 

 greenish lines is rather distinct in appearance, it intergrades with 

 more strongly sculptured shells which closely resemble the sculp- 

 tured form of D. t. jaryensis, which, however, has more distinct 

 43 



