ortmann: south American naiades. 633 



tremely elongated and dilated at the end (button-like), and probably is in life 

 never entirely withdrawn into the shell (hence the gaping margins). In addition, 

 the branchial opening is said to be closed below (Simpson), but I have not been 

 able to confirm this, and furthermore the pallial line does not show any indication 

 of this (having no sinus). D'Orbigny makes the positive statement that the bran- 

 chial is not closed. The anal opening is closed in ])art. 



This genus has a wide distribution in South America, from the Cordilleras 

 eastward, and from Argentina northwards into Central America, at least as far 

 as Guatemala. 



Von Ihering has given a key for the species (1910, p. 118); although this is 

 not always cjuite satisfactory, I have used it in the identification of my compara- 

 tively meagre material. Von Ihering's treatment of the genus surely has cleared 

 up a good deal, but it is not to be regarded as final. His opinion that there are 

 species of this genus in Eastern Asia [Solenaia) certainly is incorrect. We do not 

 know the anatomical structure of the latter, except that the foot is said to be 

 similarly developed. But we must not forget, that there is a North American 

 Unionid-shell {Lastena lata), which also has a foot like this. In the muscle-scars, 

 the ligamental sinus, and the beak-sculpture Solenaia undoubtedly differs from 

 the South American Mycetopoda, which according to the anatomy is a Muteline- 

 sheU. 



The species {subsinuata) of which I have studied the anatomy, has another 

 character, the partly closed anal-opening, in which it differs from all South American 

 Muteliiuv, and resembles the African members of this subfamily. This may be 

 another peculiar feature of the genus, but it is desirable that other species should 

 be examined as to this. 



66. Mycetopoda siliquosa (Spix) (1827). 

 Mycetopoda siliquosa Von Ihering, 1910, p. 120; Simpson, 1914, p. 1-458. 

 Mycetopoda bahia Von Ihering, 1910, p. 122, PI. 12, fig. 3; Simpson, 1914, p. 1463. 



According to Simpson, M. legumen (Von Martens) and M. clessini Von Ihering 

 belong here. 



Type-locality. — Rio Paraguassu, Bahia, Brazil. 



Other Localities. — Rio Piracicaba, Piracicaba, Sao Paulo, Brazil (Von Ihering, 

 1893); Rio Sao Francisco, ^'illa Nova, Sergipe (not Bahia), Brazil (Von Ihering, 

 M. bahia). 



Neio Locality. — Lagoa Salgado, Bahia, Brazil (upper Rio Salitre, tributary to 

 Sao Francisco) (J. D. Haseman coll., November 10, 1907). Two specimens. Two 



