NO. l8 MENHADEN, GENUS BREVOORTIA — HILDEBRAND 2/ 



2.85 to 3.2 in Standard length ; and fin low, its margin nearly straight, 

 with a very narrow sheath of scales at base, its origin about under 

 tip of last ray of dorsal, its base 5.25 to 6.1 in standard length; ventral 

 fin with an oblique and somewhat convex margin, the innermost ray 

 about two-thirds the length of the outermost one, the length of fin 3.5 

 to 4.25 in head (see fig. 9, C) ; pectoral fin short, not falcate, failing 

 to reach base of ventral by a distance varying from half to a whole 

 diameter of eye, leaving 3 to 6 scales exposed between its tip and base 

 of ventral, its length 5.6 to 6.0 in the standard length, and 1.8 to 2.0 

 in head ; axillary appendage moderately long in large examples, short 

 in small ones, 2.2 to 4.7 in head. 



Color of preserved specimens dark grayish on back ; sides yellowish 

 to brassy; a large black shoulder spot, not followed by smaller dark 

 spots ; fins all plain. 



Study material. — The foregoing description is based on 15 speci- 

 mens no to 285 mm. in total length, 87 to 223 mm. in standard 

 length. These specimens are in part in the United States National 

 Museum, Washington, D. C, and in part in the Museum of Com- 

 parative Zoology, Cambridge, Mass. ; the place of collection is not al- 

 ways definitely stated for some of the specimens. The data as to local- 

 ities are quoted from the labels as follows : Sambaia,^ Rio Janiero, and 

 Paraguay.^ 



Relationship , and a parallel comparison. — The general relationship 

 of this species and the North American members of the genus is 

 shown in the account of pcctinata (p. 24). It dififers from its South 

 American congener in the notably smaller scales, a difference actu- 

 ally greater than shown, by the enumerations given in the descrip- 

 tion. If scales from the middle of the side below the origin of the 

 dorsal are compared with those of pectinata from the same part of 

 the body, and in examples of equal size, those of aurea are only about 

 two-thirds as large as those of pectinata. This prominent difference 

 is not fully evident from the enumeration of the oblique series along 

 the middle of the side because the scales are less closely imbricated in 



3 These specimens were collected by the Thayer expedition to Brazil. Sambaia 

 could not be found on any map at hand. Accordingly the Brazilian ichthyolo- 

 gist, Dr. Joao de Paiva Carvalho, was consulted, who replied by letter that 

 there apparently is no Sambaia in Brazil, and suggested that the Sambara River, 

 one of many coastal streams between Bahia and Rio de Janeiro, might be 

 intended. He pointed out that the "r" in Sambara might somehow have been 

 changed to "i" ; a very plausible explanation. 



* See footnote 2, under B. pectinata (p. 24) for an explanation of the locality 

 "Paraguay." 



