486 



MEMOIRS OF THE CARNEGIE MUSEUM. 



Ill atldition, the Carnogio Museum possesses two specimens labeled "dlipticus, 

 Brazil," from the Holland Collection, and one specimen labeled "tmiUistriatus, 

 Brazil," from the Juny Collection. 



Distribution. — The new localities represented in the collection made by Hase- 

 man extend the range southward (southwestward) along the coast of Brazil beyond 

 Rio de Janeiro into the southern portion of the state of Sao Paulo in the small 

 coastal streams. The established range thus reaches from the Rio Paraguassu 

 in the North to the Rio Ribeira in the South. 



Remark.^. — My material is entirely insufficient for the study of the various 

 forms regarded as belonging here. Originally Von Ihering was inclined to unite all 

 these forms with granular beak-sculpture into one species; but later he divided them 

 according to the character of the beak-sculpture, although he admits that there is 

 great variation in this respect. Simpson unites them again, at least in part, but 

 he lets granulifenis Dunker stand, and even adds a new species, D. semigranosus}^ 



My specimens also vary in the development of the beak-sculpture and in the 

 shape of the shell, but they might very well be forms of one and the same species. 

 The two soft parts at hand are those of males, and the structure of the female is 

 unknown. 



The two young specimens from Iporanga show the granular beak-sculpture 

 very well, and I should call them D. granosus by all means. Simpson (1914, p. 

 1249) has described from the same river-system (Rio Ribeira) at Iguape, Sao Paulo, 

 Brazil (near the mouth), a D. mimus, and Marshall (1917, p. 383, pi. 51, figs. 3-6) 

 has redescribed and figured it. It is founded upon two specimens, larger than 

 mine, and differing somewhat from each other in their proportions, and also from 

 my specimens, but the differences may be individual. The measurements are: 



My specimens agree very well with the figures and description, except that there 

 is no lurid-purple in the nacre, which is dull (lurid) whitish. 



'■'Habitats: "Sao Paulo River" (location unknown); " Ponte Grande" (location unknown); 

 " Os Perus," Sao Paulo, Brazil. Marshall (1917, p. 387) redescribes and figures this species, and gives 

 as type-locality: Rio Tiet^, Sao Paulo, and the additional localities " Ponte Grande, Sao Paulo; Os 

 Perus; and Ponta Grossa, Parand." The location of Ponte Grande is still unknown. Ponta Grossa 

 is on the headwaters of the Rio TihaRV, trilnitary to the Paraml Panema. 



