FISHES OF WEST COAST OF PERU. 45 



Family ATHERINIDAE. 



THE SILVEKSIDES. 



KEl' TO GENERA. 



a*. Premasillaries not freely protractile, the skin of upper jaw mesially con- 

 tinuous with that of the forehead. 

 b^ Teeth simple, pointed, arranged in villiform bands. 

 c\ Vomerine teeth usually present, at least in the young ; dorsal spines 4, 



distinct Atherinopsis, p. 45. 



c^. No vomerine teeth ; first dorsal represented by a single rudimental 



spine Protistius, p. 46. 



a'. Premaxillaries freely protractile, the skin not continuous with that of the 

 forehead; scales cycloid, of small size (67 to 105), soft dorsal and anal 

 mostly without scales BasilichtJiys, p. 47. 



Genus ATHERINOPSIS Girard. 



68. ATHERINOPSIS KEGIU3 (Humboldt). 

 PEJE-EEY DE EIO. 



Atherina regla Humboldt in Cuvier and Valenciennes, Hist. Nat. Poiss., 



vol. 10, 1S35, p. 352 ; Coast of Peru. 

 Atherina microlepidota Jenyns, Zool. Voy. Beagle, Fish., vol. 2, p. 78, pi. 16, 



figs. 1, 2, a, h; Valparaiso. 

 Gastropterus archaeus Cope, Proc. Amer. Philos. Soc, vol. 17, 1878, p. 700; 



Arequipa, Peru. — Eigenmann, Cat. Freshwater Trop. and South 



Temp. Amer., 1910, p. 464. 

 Pisciregia beardsleei Abbott, Marine Fishes of Peru, Proc. Acad. Nat. Sci. 



Phila., 1899, p. 342 ; Callao. 

 Atherinopsis regitis Steindachner, Herpet.-ichthyol., Ergebnisse einer Reise 



nach Siidamerika, Denkschr. Akad. Wiss. Wien, vol. 72, 1902, p. 39; 



Rio Tambo, southern Peru. — Eigenmann, Cat. Freshwater Fish. Trop. 



and South Temp. Amer., 1910, p. 465. 

 Gastropterus beardsleei Eigenmann, Cat. Freshwater Fish. Trop. and 



South Temp. Amer., 1910, p. 464. 



Two specimens, field No. 427, 11.1 and 12.3 cm. in length, from the 

 Rimac River near Lima. 



Head 4.04 in length; depth 5.3 to 5.5; eye 4.5 to 5 in head; snout 

 2.85 to 3 ; maxillary 2.85 to 3 ; intercrbital 2.65 to 2.T5 ; pectoral 1.2 to 

 1.3 ; ventrals 2.5 ; D. IV, 1, 11 ; A. I, 15 ; scales about 20-90-3. 



Head broad, depressed ; top of head, cheeks, opercle and suborbital 

 scaled; snout, preorbital and maxillaries naked; teeth in jaws in 3 

 or 4 series, large, recurved, the outer row somewhat larger than the 

 others; a number of small recurved teeth on vomer, these small 

 and may easily escape detection in the mucus about them; pre- 

 maxillary not protractile, its skin continuous with that of the fore- 

 head; interdorsal space very short; origin of first dorsal slightly 

 anterior to middle of distance from tip of snout to tip of caudal; 

 anterior rays of second dorsal and anal elongate ; caudal forked, the 

 lobes not widely diverging; gillrakers short and stout, 4-|-15. 



