84 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



of fin 2.55 to 3.1 in liead; ventral inserted under base of about the 

 sixth ray of dorsal, and approximately an eye's diameter nearer base of 

 pectoral than origin of anal; pectoral moderately long and pointed, 

 failing to reach base of ventral by rather less than diameter of eye in 

 large examples, by less than pupil in smaller ones, inserted about 

 equidistant from base of ventral and middle of eye, the fin 1.6 to 1.75 

 in head, 4.7 to 5.0 in length. 



Color in alcohol bluish brown or bluish gray above, the color of 

 back changing abruptly to silvery somewhat above middle of side; 

 dorsal, caudal, and anal more or less dusky; other fins pale; sides with 

 2 parallel rows of vertically elongate dark spots; the upper series con- 

 sisting of about 10 spots extending backward from upper posterior 

 angle of opercle and situated in the lower part of the bluish color of 

 the back; these spots indistinct in some specimens; the second row 

 generally consisting of about 8 spots, beginning behind margin of 

 opercle, and somewhat below middle of body; spots of second row 

 much more prominent than those of upper row in large specimens, 

 though missing in the smaller ones ; a few large specimens with a third 

 row consisting of 2 or 3 obscure spots ; large specimens with indefinite 

 dark lines along the rows of scales on back. 



Twelve specimens, ranging in length from 125 to 270 mm., collected 

 at Callao and in Chilca Bay, Peru, are at hand. A specimen 270 mm. 

 long (212 mm. to base of caudal) (U.S.N.M. No. 127806), taken by the 

 Mission at Chilca Bay, has been selected as the type. The following 

 enumerations and proportions are based on this specimen: D. 18; A. 15; 

 P. 16; scales 55; ventral scutes 19 + 18; dorsal scutes 26; gill rakers 131. 

 Head in length 3.1; depth 2.9. Eye in head 5.6; snout 4.0; maxillary 

 2.1; mandible 1.85; interorbital 4.85; longest dorsal ray 1.85; anal base 

 2.95; and pectoral 1.75. In the type the upper row of black spots 

 is rather obscure, the second row is very prominent, and dark lines 

 along the rows of scales on the back are evident. 



This species does not seem to be identifiable with Alausa maculata 

 or A. coerulea both of Cuvier and Valenciennes (1847, pp. 430 and 

 432), which have been considered as belonging to the genus Ethmidium 

 (or Potamalosa) by authors. Their generic relationship cannot be 

 certainly determined, however, from the descriptions, which are quite 

 inadequate and fail to mention dorsal scutes. Peruvian specimens, 

 indeed, have been identified with A. maculata by authors, as shown 

 by the synonymy given. These identifications probably were incor- 

 rect. That, at least, seems true of Fowler's identification (1940b, 

 p. 745), whose specimens are now before me. 



Clupea notacanthus Giinther (1868, p. 443) also was based on speci- 

 mens from Valparaiso, Chile. This species certainly belongs to 

 Ethmidium, as dorsal scutes are mentioned in the original description. 



