ANNOTATED LIST OF THE SPECIES 131 
15845, 1, 200 mm., Lago Cashiboya, Allen, August, 1920. 
15850, 1, skin, 650 mm., La Merced (about 2500 feet), Senor Ecuador Praeli, 1918. 
16004, 1, 273 mm., to end of scutes, Rio Pacaya, Allen, August, 1920. 
The colloquial name foro is supplied by Fowler. 
Genus 48: TRACHYDORAS Eigenmann 
Trachydoras Eigenmann, 1925, Trans. Amer. Phil. Soc., X XII, 337. 
Fig. 18. The Cocamita, steam-launch with the least draft, and ascending 
streams the farthest, of the Iquitos fleet. Carries mail and passengers. Rio 
Pachitea. 
Type: Trachydoras atripes Eigenmann 
Amazonia to basin of Rio Paraguay 
Maxillary barbels fringed and just reaching the gill opening or shorter; the 
bases of the mental barbels united by a membrane; eye beyond the middle of the 
head; the dorsal spine serrate on both margins; caudal forked; adipose short and 
sometimes continued as a ridge; second air bladder minute or wanting; opercle, 
preopercle and coracoid process granular; first lateral scute large, connecting 
with humeral process and dorsal plate; fontanel not continued backward as a groove; 
snout short, anterior nares nearer snout than to posterior, or equidistant; mouth 
narrow; teeth weak or wanting. 
88. TRACHYDORAS NATTERERI (Steindachner) 
Oxydoras natterert Steindachner, 1882 (1883), Sitzb. KIx. Akad. Wiss. Wien, XLIII, 104, pl. i, fig. 2; 
pl. iv, figs. l1-la, Teffé. 
