ortmann: south American naiades. 



549 



Material Represented in the Carnegie Mmeimi. — Rio Piracicaba, Sao Paulo, 

 Brazil (Von Ihering, donor, cotypes or tqpotypes). Two six'cimens. Rio Tiet^, 

 Salto das Cruzcs, Sao Paulo, Brazil (J. D. Haseman coll., September 22, 1908). 

 Four specimens, two of them with soft parts. Rio Tiete, 25 miles above Itapura, 

 Sao Paulo, Brazil (J. D. Haseman coll., September 27, 1908). Eight specimens, 

 six of them with soft parts. 



Distribution. — Rio Tiete and Rio Piracicaba in S:lo Paulo, headwaters of Rio 



Parana. 



Von Ihering has given a detailed description of this species, pointing out its 



differences from the allied species. He believes that specimens with the beaks 



more distant from the anterior margin are males. I cannot control this, since I 



have no males among those of my specimens with soft parts, but the percentage 



given for the location of the beaks in the males (28 to 30 pr. ct.) is not represented 



in my measurements, and this would tend to confirm Von Ihering's observation. 



It is to be noted that my smallest specimens (Nos. 1 to 5 from Itapura) exceed in 



height the figures given by Von Ihering, and thus young shells are proportionally 



higher: the older ones become longer on account of a prolongation of the posterior 



end of the shell (best seen in No. 6 from Itapura). 



Me.\surements. 



Anatomy. — I have the soft parts of eight specimens, all of which are females, 

 three of them gravid. One of the latter had eggs; one had immature, and the 

 third mature glochidia. For the breeding season the dates of collection (September 

 22 and 27) should be noted. (Mature glochidia were found on Sept. 22.) 



Von Ihering (1893, p. 79) describes the soft parts of two males. Of these, 

 one had the branchial opening closed in front, the other open. This is the species 

 of Castalina, to which I have referred previously (Ortmann, 1911, p. 118). In 

 none of my females is there an anterior mantle-connection in front of the branchial 

 opening. Therefore this seems to be the normal condition in this species, although 

 it should he born in mind that this connection at its best is very slight, and might 

 l)e easily torn by rough handling. 



The anal opening is described by Von Ihering as also differing in his two 



