554 MEMOIRS OF THE CARNEGIE MUSEUM. 



age. In trying to use this key, I generally met with \\w difficulty that my specimens 

 were intermediate between the alternatives given in it. But, as I said, my material 

 is too scanty to bring order out of this confusion, yet I shall try my best to give an 

 account of the material at hand. 



The geographical distribution of the species of this genus is interesting. Ac- 

 cording to Von Ihering (1910, p. 130) their metroi)olis is in the Amazon-drainage, 

 whence the forms extend into Guyana and the upper Parana-drainage. But on 

 account of the great uncertainty prevailing with regard to the various species no 

 details can be given. 



32. Castalia acuticosta Hupe (1857). 



Glochidium: Text-fig. 4, m, p. 469. 



Castalia acuticosta Hupe, 1857, p. <77, PI. 14, fig. 3; Howerby, XVII. 1869, PI. 3, 



fig. 12. 

 Tetraplodon acuticosta Von Ihering, 1910, p. 128. 



Type-locality. — Brazil. (Von Ihering says that Castelnau collected this 

 species in Goyaz, but I cannot find this fact mentioned in Hupe's paper.) 



Other Localities. — Rio Araguay, Goj^az, Brazil (Von Ihering, 1910, p. 135); 

 Lagoa do Goral, Goyaz, Brazil (Von Ihering) (drainage of Rio Araguay, tributary 

 to Tocantins). 



New Localities. — Sand-bar of Rio Tapajos, Santarem, Para, Brazil (J. D. Hase- 

 man coll., December 6-12, 1909). Eight specimens, one of them a male with soft 

 parts. Center of Rio Guapore, near Rio Sao Simao, Matto Grosso, Brazil (J. D. 

 Haseman coll., July 20, 1909). Three specimens, with soft parts, male, and gravid 

 females. Rio Guapore, Sao Antonio de Guapore, Matto Grosso, Brazil (J. D. 

 Haseman coll., Jul.y 31, 1909). Four specimens. Rio Machupo, San Joaquim, 

 Bolivia (J. D. Haseman coll., September 1, 1909). Three young specimens, with 

 soft parts, probably males. 



In addition, the Carnegie Museum possesses a fine specimen from the Juny 

 collection, without locality. 



Distribution. — Southern tributaries of the Amazon, from Tocantins and Ara- 

 guay in Goyaz, and Rio Tapajos in Para, to the Madeira (Guapore and Machupo) 

 in Matto Grosso and Bolivia. 



This species belongs to those with elevated beaks, although the beaks are here 

 far less prominent than in turgida, fxtro, and hanleyana. It is a small species 

 (maximum length 35 mm.); but that specimens about 25 mm. long are mature is 

 shown by the fact that at that size they may be gravid. 



