very light below, Back with narrow, well defined deep brown 
lines; one to each row of scales, usually little less than 1/3 
its exposure width, slightly waved and some of lower ones 
little broken or irregular. Slight dusky shade in axille, 
Fins brown, with dusky shade at end of spinous dorsal. Length 
O16 mM» 
Compared with M. undulatus from Maryland, the latter differs 
in the. dark lines far less regular, more zig-zag, specked and not 
following evenly within the inclined scale rows, Its soft dor- 
sal is rather finely spotted, while the Patagonian species shows 
anarrow dark or dusky streak in each membrane parallel and be- 
tween the rays. M. undulatus has more barbels, or usually 5 
pairs and Chesapeake Bay examples do not show any difference 
scale structure, or basal striae 10 and apical denticles 38, 
in specimens 223 mm, long. 
/ 
Starks compared Para examples with Jamaican examples of 
M. furaiant ” ead Sound the Brazilian fish with a sharper 
snout projecting further over the mouth, head less deep and 
more depressed above eyes, and the other characters agreeing 
with our material, A comparison with M. opercularis listed 
Santo Deminge-? shows the latter a distinct species, embrace 
ing the characters alleged by Starks, except we do not detect 
149 Stanford Univ. Pubs.,1913, p. 54. 
150 Proc.Acad,Nat.Sci,rnila.,1919, p. 129. 
151 Copeia, no, 24, Nov, 19, 1915, p. 50. 
