596 MEMOIRS OP THE CARNEGIE MUSEUM. 



of branchial ()])oniiijii; with distinct, but small papillsD. Palpi rather small, semi- 

 circular, shortly truncated posteriorly, thus forming posterior margins, which are 

 not connected. 



Gills (PI. XLVII, figs. 4a, b) long and narrow, the inner considerably wider 

 than the outer, chiefly anteriorly. Anterior end of inner gill immediately behind 

 the pali)i. Inner lamina of inner gill entirely connected with abdominal sac. 

 Septa well develojied, those of the non-marsupial gills alternately somewhat stronger 

 and weaker, best seen in the outer gill of the female (PL XLVII, fig. 46). Inner 

 gill of female marmpial for nearly its whole length, with more uniform, thicker, 

 but not more ci'owded septa, which have the usual swellings near their contact 

 with the outer lamina. 



2. Group of Anodontites ohlusa. 

 Simpson, 1914, p. 1453. 



Shell not very oblique, subovate or subelliptical, rather short, lower margin 

 convex. Epidermis dull, greenish, often with rays, concentrically lamellarly 

 wrinkled. Prismatic border narrow. 



The few forms belonging here are closely aUied to the first group, and have 

 indeed been placed in the section of Styganoclon by Simpson. They are shorter, 

 higher than those of the crispata-group, with more inflated beaks, and have an 

 unusual development of color-rays. The sculpture of the eiiidermis is much like 

 that of Icnebricosa and clcsmii, and consists of close, sublamellar, concentric wrinkles, 

 here and there subreticulated. 



51. Anodontites obtusa (Spix) (1827). 

 Anodon obtusum Spix, 1827, PI. 22, fig. 3; Wagner, Ibid, ]:>. 30. 

 Anodon lituratum Spix, Ibid, PI. 22, fig. 4. 



Anodonta obtusa and litturala Hupe, 1857, pp. 86, 87, PI. 17, fig. 4. 

 Ayiodon obtusus Sowerby, XVII, 1867, PI. 12, fig. 39. 

 Anodon lUurata Sowerby, Ibid, 1868, PI. 20, fig. 78. 

 Anodonta obtusa Von Ihering, 1890, p. 159. 

 Glabaris obtusus and lituratus Simpson, 1900, p. 931. 

 Anodonta {Glabaris) obtusa Germain, 1910, ]). 63, PI. 3, figs. 14, 15. 

 Anodontites obtusus and lituratus Simpson, 1914, pp. 1453, 1454. 



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



Other Records. — Rio Paraguassii (Von Ihering, 1910, p. 139); Rio Sao Francisco, 

 Villa Nova, Scrgipe, Brazil (Von Ihering); Rio Sao Francisco, Joazeiro, Bahia, 

 Brazil (Von Ihering); Rio das Velhas, Minas Geraes, Brazil (Von Ihering) (upper 



