ortmann: south American naiades. 635 



67. INIycetopoda staudingeki (Von Iheuing) (1890). 

 Mijcetopus staudingeri Von Ihering, 1890, p. 130, figs. A, B. 

 Mijcetopoda staudingeri Simpson, 1900, p. 934; Von Ihering, 1910, p. 121. 

 Mijcetopoda siliquosa staudingeri Simpson, 1914, p. 1460. 



Type-locality. —Rio Huayabamba, Peru (tributary to Rio Huallaga). 



Additional Locality. — Rio Huallaga, Peru (Von Ihering). 



Locality Represented in Carnegie Museum. — Maranon, Upper Amazon (Hart- 

 man collection). One specimen. 



Di.^tribution. — Headwaters of the Amazon in Peru; a variety {cequatorialis 

 Von Ihering) in Ecuador. 



Our specimen agrees very well with Von Ihering's description and figures, 

 chiefly with fig. .4 (which is supposed to be a male) but it to a certain degree stands 

 between figs. .4 and B (See measurements of height). The postsinual position 

 of the posterior adductor-scar is evident and remarkable, and it seems, indeed, 

 that this is an important taxonomic character. The posterior end of the upper 

 margin (behind the ligamental sinus) is in my specimen not so greatly elevated 

 as in Von Ihering's figures. 



Measurements. 



In 1910, Von Ihering gives for the height 35 to 37 pr. ct. of the length, which 

 does not exactly agree with his original figures. The location of the beaks is ac- 

 cording to him is 27 to 28 pr. ct. of the length. 



68. Mycetopoda suBsiNUATA (Sow^rby) (1868). 

 Mycetopus subsiiitiatus Sowerby, XVI, 1868, PL 4, fig. 10; Von Martens, 1900, 



p. 540, PL 41, fig. 5. 

 Mycetopoda subsinuata Simpson, 1900, p. 934; Von Ihering, 1910, p. 120; Simpson, 



1914, p. 1461. 



Type-locality. — Bogota, Colombia. 



Other Localities. — Ecuador (Von Ihering); Paso Antonio, West Guatemala 

 (Pacific slope) (Von INIartens). 



New Localities. — Maranon, Upper Amazon (Peru) (Hartman coll.). Three 

 complete specimens, four left valves. Rio Conchins, INIaya Farm, Quirigua, 

 Guatemala (Atlantic slope, to Rio Montagua) (A. A. Hinkley coU., February 6, 



