438 PROCEEDINGS OF THE NATIONAL MUSEUM Vou. 113 
Papyraceus (Mawe) is the only well-known Drymaeus from that 
country. WD. interpunctus belongs to the group of poecilus. I have 
seen other specimens (CM 62.40524) from Sao Leopoldo, near 
Porto Alegre, Rio Grande do Sul, Brazil (the label has the handwriting 
of von Ihering), and also another specimen in the Museo Argentino de 
Ciencias Naturales from Puerto Aguirre, Iguazti Falls, Misiones, 
Argentina, which is an intermediate western point between the type 
locality and that of Porto Alegre. Thus, this species is distributed 
east of the Paran4é River in the north, and west of the Uruguay River 
in the south. 
This shell immediately recalls Succinea by its shape, color, and 
thinness. The species is peculiarly separated from all the other known 
species of Stenostylus by the fact of its occurrence on the opposite side 
of the continent; the connection with the western species has probably 
taken place along the Rio Negro. The nearest species is D. (S.) 
colmeirot Hidalgo, from Ecuador. The subgenus Stenostylus seems 
to be rather limited in number of forms and specimens. The only 
species from the west that I had an opportunity to examine is D. (S.) 
troschelt (Philippi) from Peru (in the Museum of Comparative 
Zoology). 
Drymaeus (Stenostylus) succineus (Pilsbry) 
Drymaeus succinea Pilsbry, Manual of conchology, ser. 2, vol. 14, p. 160, 1902. 
Type locality: Marajo Island, mouth of the Amazon River, Brazil. 
Complementary description: Shell succineiform, very glossy, with 
almost 5% whorls (original description indicated only 4% whorls), the 
last being a little more than four-fifths the height, and the diameter 
three-fifths the total length. Suture simple, scarcely inclined (6°) 
but waved; surface polished with wide lines of growth. Protoconch 
perfectly punctate as is peculiar in Drymaeus and with reticulation 
easily distinguishable; this sculpture is continued to the beginning of 
the third whorl and from there vanishes gradually. Penultimate 
whorl about one-seventh the length and one-fourth the larger diameter. 
Aperture large, nearly two-thirds the total length and one-third the 
width. Peristome very thin. 
Four specimens (USNM 32105) from Marajo Island, Brazil, 
collected by J. B. Steere; the largest measures: Height 13.5 mm., 
diameter 7.3 mm., last whorl 11.5 mm., penult. whorl 1.9 mm., aper- 
ture 8x4.5 mm. ‘These specimens belong undoubtedly to the type 
lot, so the original type locality given, “Amazon River,” is now re- 
stricted to Marajo Island. 
