ortmann: south American naiades. 



559 



Tetraplodon iitjlalus Von Ihering, 1910, p. 126; 1915, p. 12. 



Type-locality. — Parana River, C'orrientcs, Argentina. 



Other Localities. — Lower Parana River (Von Ihering) ; small tributaries of the 

 Parana (D'Orbigny) ; Rio Paraguay, near Rio Apa, Paraguay (Von Ihering) ; Rio 

 Paraguay, San Luis de Caceres, Matto Grosso, Brazil (Von Ihering). 



Locality Represented in Carnegie Museum. — Rio Paraguay, San Luis de Caceres, 

 Matto Grosso, Brazil (J. D. Haseman coll.. May 24, 1909). Two specimens. 



Distribution. — Positively known only from the Parana and Paraguay Rivers in 

 Argentina, Paraguay, and Brazil. Specimens reported from the Amazon-drainage 

 in Bolivia probably do not belong here. 



My identification of this species depends partly on Von Ihering's key, partly 

 on D'Orbigny's original description and figures of specimens from Gorrientes, 

 and on the locality. It is a species with low beaks, the shell is oval, but for the 

 rest. Von Ihering's key is insufficient. One of my si^ecimens is rather small, and 

 the beak-sculpture reaches the lower margin ; in the other, it falls short of it. The 

 beaks are located at 21 and 24 pr. ct. (21 pr. ct. given by Von Ihering). The shell 

 is about as long as in pectinata, and is thicker. The bars of the beak-sculpture 

 in my specimen are rather numerous, but not very sharp. The adductor-scars 

 agree with Von Ihering's account. Thus I have no doubt that my specimen repre- 

 sents C. inflata, although the essential characters of this species are yet obscure. 



Measurements. 



D'Orbigny's text 



D'Orbigny's fig. of specimen 

 from Corrientes 



Length. 



29 mm. 

 36 " 

 65 " 



35 " 



Height. 



Beaks. 



23 mm. =79 pr. ct. of L. 20 mm. =69 pr. ct. of L. at 6 mra. =21 pr. ct. of L. 



26 



25.5 



= 72 

 75 



= 73 



22.5 



24 



=63 

 60 



S.5 



8.5 



= 24 



= 24 



Von Ihering does not give detailed measurements, but only says that the maxi- 

 mum length is 51 (1893) and 60 mm. (1910). 



37. Gastalia undosa Von Martens (1885). 



Shell: Plate XXXIX, figs. Sa-d. 



Castalia xmdosa Von Martens, 1885, p. 148; Von Ihering, 1893, p. 84; Nehring, 



1893, p. 165. 

 Castalina undosa Simpson, 1900, p. 866; 1914, p. 1207. 



Tetraplodon undosus Ortmann, 1911a, p. 117, PL 6, fig. 7, PI. 7. fig. 7 (anatomy). 

 Type-locality.— Tiio Piracicaba, Piracicaba, Sao Paulo, Brazil. 



