558 



MEMOIRS OF THE CARNEGIE MUSEUM. 



New Localities. — Amazon River, Para, Brazil (Hartman collection). Two 

 specimens. Sand bar of Rio Tapajos, Santarem, Para, Brazil (J. D. Haseman 

 coll., December 6-12, 1909). One odd (right) valve. 



Distribution. — Known hitherto orily from the Rio Hao Francisco, and only 

 from the description and figure of Hpix and Wagner. Its discovery in the Amazon 

 and Tapajos in Para thus extends its range into the lower basin of the Amazon. 



The characters of this species have been established by Von Ihering, and, 

 although it is hazardous to define an old, often misunderstood, and poorly figured 

 form, without having abundant material, the fact that our specimens well agree 

 with the account given by Von Ihering, demonstrates that he is right. The chief 

 characters of this species are found in the low beaks, the rather elongated outline, 

 and rather anterior position of the beaks. The beak-sculpture is described as 

 "mostly" reaching the ventral margin. This is actually the case in one of our 

 specimens from the Amazon and in the half shell from the Tapajos. In the other 

 individual from the Amazon the radial bars are shorter and cover only a little 

 more than half of the shell. 



Remarks. — Von Ihering gives the location of the beaks as 25 pr. ct.; my speci- 

 mens agree with this very well. 



C. jur liana (Von Ihering, 1910, p. 126) from the Rio Jurua (southern tributary 

 of the Amazon in western Brazil) is closely allied. It is founded upon a single 

 specimen, which differs chiefly in the location of the beaks (at 37 pr. ct.), and certain 

 other characters, which at least in part are connected with this. It may finally 

 prove to be only a form of pectinata. 



Our specimens have about the size given by Wagner in the text (l. c., p. 33) 

 28 to 31 mm.; while Spix's figures (PL 24, figs. 3, 4) are considerably larger (L. 

 over 40 mm.) . Thus they apparently are enlarged. C. juruana is larger, L. 46 mm. 



36. Castalia inflata D'Orbigny. (1835). 

 Casialia inflata D'Orbigny, 1835, p. 43. 

 Castalia ambigua D'Orbigny, 1843, p. 598, PI. 72, figs. 4-6. 

 Castalia ambigua inflata Von Ihering, 1893, p. 88. 

 Castalia quadrilatera Von Ihering, 1893, p. 89. 



