428 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



material. As the fish grow the scales become denser and extend 

 farther on the fins. The adults are much less bright silvery than the 

 young herein described. 



Range. — Both coasts of America; on the Pacific coast from the Gulf 

 of California to Chile and on the Atlantic from Cape Cod to Brazil. 

 Recorded also from Africa. 



MUGIL THOBURNI Jordan and Starks 



Liza 



Mugil thohurni Jordan and Starks, in Jordan and Evermann, 1896, p. 812, 

 Galapagos Islands (original description; compared with M. incilis; range). — 

 Nichols and Murphy, 1922, p. 506, Paracas Bay, Peru.— Meek and Hilde- 

 BRAND, 1923, p. 278 (references; description, based on type material; range). 



This species is not included in the collections from Peru now at 

 hand. I have examined several specimens from the GaUpagos 

 Islands, which agree with curema in the number of anal rays and in 

 having the fins rather densely covered with scales. However, this 

 species differs from curema and all the other species herein recognized 

 from Peru in the thick upper lip and the smaller scales, the count 

 for the oblique series between the upper anterior angle of the opercle 

 and base of caudal in five specimens being 45 and 46. 



Range. — Guatemala to Peru and the Galdpagos Islands. 



Family ATHERINIDAE: Silversides 



Body generally quite elongate, compressed; vertebrae more than 

 30; mouth moderate or small, usually with pointed teeth; gills 4; 

 lateral line absent, or incompletely and irregularly developed; anal 

 fin with a single spine in American species; first dorsal with 3 to 9 

 flexible spines in Peruvian species, rarely missing; pectoral placed 

 high and more or less pointed in American species; ventral fins ab- 

 dominal, with 1 spine and 5 soft rays. 



KEY TO THE GENERA 



a. Premaxillaries protractile; scales on top of head not reversed in imbrication. 

 b. Head rather long and pointed, not abruptly shortened posteriorly; anal 



fin short, with about 14 to 16 rays Austromenidia (p. 428) 



bb. Head short, blunt, abruptly shortened posteriorly, the margin of opercle 



little convex; anal fin long with about 25 to 30 rays-Eurystole (p. 431) 



aa. Premaxillaries not protractile; scales on top of head reversed in imbrication; 



anal fin small, with about 13 to 16 soft rays Basilichthys (p. 433) 



Genus AUSTROMENIDIA Hubbs, 1918 



Body quite elongate; belly rouned; vertebrae numerous, about 48; 

 head moderately low; snout rather pointed; premaxillaries protractile; 

 teeth well developed in both jaws; scales small, extending forward on 

 head and cheeks; first dorsal, over space between base of ventral and 

 origin of anal, remote from second dorsal, usually with five or six 

 spines; pectoral fin not reaching base of ventral. 



