184 Field Columbian Museum — Zoology, Vol. V. 



<>!>. Thyrina Jordan & Culver. 



Thyrina Jordan & Culver, Proc. Cal. Acad. Sci., 1896, 419. 

 (Type, Thyrina evermanni Jordan & Culver.) 



Body elongate, compressed, the abdominal region before ventrals 

 compressed into a bluntish edge or keel; pectoral fin falcate, longer 

 than the head; anal fin very long, its origin in advance of spinous 

 dorsal; scales cycloid. 



To this genus belong only the two following species : 



KEY TO THE SPECIES OF THYRINA. 



a. Anal rays about 1, 24; base of anal fin 2^ in page 

 body; pectoral 3^2 in body; ventral fins pale . . . .[evermanni] 184 



aa. Anal rays about 1 , 21; base of anal fin 3 in 



body ; pectoral 4 X in body ; ventral fins black crystallina 1 84 



Thyrina evermanni Jordan & Culver. 



Thyrina evermanni Jordan & Culver, Proc. Cal. Acad. Sci., 1895, 419; 

 Mazatlan: Jordan & Evermann, Bull. 47, U. S. Nat. Mus., 1896, 804. 



Brackish water near Mazatlan. 



Head 4^; depth 4% to 5; D. iv-i, 7; A. 1, 23 to 25; scales 9-36. Body 

 elongate, much compressed; the belly sharp-edged, concave on each side below 

 pectorals, the edge almost carinate; back narrow; mouth small, terminal, 

 jaws curved; teeth moderate, those in the upper jaw the longer; snout 3? in 

 head; eye i 2 X\ origin of spinous dorsal over about 6th anal ray, midway be- 

 tween base of caudal and edge of preopercle ; pectoral fin % longer than head ; 

 •anal fin long; its base 2^ in body; gill rakers long and slender, numerous; 

 scales cycloid. 



Color light green, much dotted above, translucent below; a dark lateral 

 stripe; no black on dorsal fin. Length about 3 inches. 



This species known only from the estuary at Mazatlan, its type locality. 



174. Thyrina crystallina (Jordan & Culver). 



Atherinella crystallina Jordan & Culver, Proc. Cal. Acad. Sci., 1895, 

 420; Rio Presidio, below Presidio, Sinaloa. 



Thyrina crystallina Jordan & Evermann, Bull. 47, U. S. Nat. Mus., 

 1895, 804; Rio Presidio, below Presidio, Sinaloa. 



Basin of the Rio Presidio. 



Head 4%", depth 4 l A to 5; D. iv-i, 8; A. 1, 21; scales 11-40. Body 

 rather deep, compressed, the belly sharp-edged; mouth small, ter- 

 minal; jaws curved; teeth rather strong, the outer curved, those in the 

 upper jaw the longer; snout 3X in head; eye 2><; origin of spinous 

 dorsal behind anal, midway between gill opening and base of caudal; 

 base of anal one-half longer than head, 3 in body; pectoral $ longer 

 than head; gill rakers numerous, long and slender; scales cycloid. 



Color translucent green, with considerable dusky dottings; a dark 

 silvery lateral stripe; first dorsal and base of anal dusky. Length 

 3^ inches. 



Known only from the type locality. 



