1370 Bulletin 4.7, United States National Museum. 



Length 3 to 8 inches. Pacific coast of Mexico; excessively common in 

 shallow bays, and entering streams; known from Guaymas and Cape San 

 Lucas to Panama; once taken at San Diego. 



Diapterus calif orniensis* GILL, Proc. Ac. Nat. Sci. Phila. 1862, 245, Cape San Lucas. 



(Coll. Xantus. ) 

 Diapterus gracilis, GILL, Proc. Ac. Nat. Sci. Phila. 1862,246, Cape San Lucas. (Coll. 



Xantus.) 

 Gerres cinereusj var. nov., EIGENMANN & EIGENMANN, Amer. Naturalist, Feb., 1891, 155, 



San Diego. (Coll. Eigenmann.) 

 Gerres gracilis, EVEEMANN & MEEK, I. c., 261. 

 Gerres calif orniensis, EVERMANN & MEEK, I. c., 263. 

 Eucinostomus calif orniensis, \ JORDAN, Proc. Cal. Ac. Sci. 1895, 469. 



1747. EUCINOSTOMUS GTJLA (Cuvier & Valenciennes). 



(SILVER JENNY; MOJARRA DE LEY; PETITE GUEULE.) 



Head3; depth 2|; eye 3 in head; snout 3|; interorbital width 3. D. 

 IX, 10; A. Ill, 8; scales 5-42-9. Body elliptical, compressed, back moder- 

 ately elevated, mouth small; end of maxillary reaching slightly past 

 vertical Irom front margin of orbit ; exposed portion of maxillary nearly 

 oblong, its width about 2 in its length, which is from 4 to 5 in the length 

 of the head; preorbital and preopercle entire. Gill rakers small and weak, 

 7 below the angle ; premaxillary groove scaled in front, the posterior part 

 naked, forming a sort of pit; longest dorsal spine 1 in head; second anal 

 spine shorter and stronger than third, its length about 3 in head; ventrals 

 reaching nearly to vent, their length If in length of head; pectorals 

 reaching front of anal, their length about 3 in length of body. Second 

 interhseinai hollow and enlarged. Color silvery, greenish, darker above; 

 no distinct longitudinal lines except in very young; upper margin of 

 spinous dorsal more or less black ; dorsal and anal fins dusky, other fins 



* The following is the substance of Dr. Gill's description of E. calif orniensis : 



Head3i; depth 2^ in young. D. IX, 10; A. Ill, 8. Scales 6-44-13. Caudal peduncle 

 slender and attenuated at middle. The diameter of eye 2f times (.09) in head ; snout 3|, 

 Interorbital area flattened, groove for the posterior processes of premaxillaries broad, 

 scaleless, semioval, and reaching vertical of ends of maxillaries, exposed portions of max- 

 illaries convex above, semicordate, twice as long as broad. Lateral line sigmoidally 

 curved. Second and third dorsal spines nearly equal, 5 in body, 1 in head, nearly twice 

 as long as last spine. Third anal spine larger than second, shorter than last dorsal one, 

 and 4 in head. Caudal ^ longer than head, equaling pectorals, and twice as long as 

 ventrals. Color silvery, with steel-blue reflections above; the fins immaculate. (Gill.) 



t A specimen ( aken at San Diego and recorded by Dr. Eigenmann as ' l Gerres cinereus, var. 

 nov.," seems to belong to Eucinostomus calif orniensis. Head 3| ; depth 2 ; scales 6-45-10 ; 

 eye equal to interorbital space, 5 in head ; maxillary just reaching front of eye ; predorsal 

 distance 2J in length; caudal fin slightly longer than head, second anal spine short, about 

 3J in head; ventral fins 1J in head. Dark punctulations every where, except on ventral 

 surface; no dark lateral bars; upper portion of spinous dorsal fin blackish; all the fins 

 finely punctate, the pectorals least so; a dark-blue axillary spot. Length about 7 inches. 

 San Diego. (Eigenmann.) 



I" Eucinostomus californiensis is generally common along the west coast of Mexico, 

 from Guaymas to Panama. It is probably, however, not found in the West Indies, .he 

 closely related Eucinostomus harengulus being apparently a different species. The speci- 

 mens called calif orniensis by Gill, having the premaxillary groove semioval or U -shaped, 

 seem to represent the adult of this species. Those called gracilis, with the premaxillary 

 groove linear, are the young or half grown. Still others, especially adults, have the 

 premaxillary groove round, forming a pit, and every intermediate character may be found. 

 At first we thought it possible to separate californiensis and gracilis as distinct species. 

 The careful reexamination of some 200 specimens leaves us wholly unable to separate 

 them, as all grades of variation occur. Apparently the premaxillary groove is linear in 

 the young, growing broader with age, but the changes very irregular. The name Eucino- 

 stomus calif orniensis has priority over E. gracilis" . (Jordan.) 



