Jordan and Evermann. Fishes of North America. 805 



more than half the eye ; first dorsal and base of anal dusky ; outlines of 

 air bladder evident through the translucent sides of body, but less so 

 than in Thyrina evermanni. Length 3i inches. Rio Presidio, near Mazat- 

 lan, Sinaloa, in fresh water; very common; the longest specimen 3i 

 inches long, (crystallinus, crystalline, from the window-like appearance 

 of the air bladder through the translucent muscles.) 



AtheriiH'lla cri/xtalliiia, JORDAN & CULVER, Fishes Sinaloa, MS., 1895, Rio Presidio, below Pre- 

 sidio, Sinaloa. (Type, No. 2685, L. S. Jr. Univ. Mus. Cotype, No. 47440, U. S. Nat. Mus. 

 Coll. Hopkins Expedition.) 



360. ATHERINELLA, Steindachner. 



Atherinella, STEINPACHNER, Ichth. Beitrage, n, 35, 1875, (panamensis). 



Body elongate, with the abdominal edge compressed into a keel. Cleft 

 of mouth very oblique; teeth hooked; scales strongly ctenoid. Upper 

 jaw protractile; pectoral very long and falcate. First dorsal small, 

 inserted behind front of long anal. Eastern Pacific. (Name a diminu- 

 tive of Atherina.) 



1176. ATHERINELLA PANAMENSIS, Steindachner. 



Head 4f ; depth 4|. D. III-l, 7 ; A. I, 21 ; scales 37 or 38-7i ; eye large, 

 3; snout 3. The broad flat interorbital space 2^in head. Profile straight 

 from snout to second dorsal. Ventral convex from base of lower jaw to 

 end of long anal, edge of abdomen forming a sharp keel. Lower jaw 

 oblique ; premaxillary protractile ; maxillary concealed by preorbital 

 when mouth is closed. Teeth in several rows, those of two outer rows 

 thickened at base and strongly incurved at tips. Pectoral very strongly 

 developed, much longer than head, falcate, as in Pelecus cultratus, which 

 this species strongly resembles. Upper pectoral ray longest, 2i in body, 

 others rapidly shortening ; ventrals short, nearer tip of lower jaw than 

 base of caudal. Spinous dorsal short and weak, inserted over tenth anal 

 ray ; soft dorsal extending farther back than anal ; lower caudal lobe 

 longest. Scales strongly ctenoid, those above lateral line longest. A 

 silver-gray lateral band dotted with black. Panama. (Steindachner.) 

 Known from one specimen 5 inches long. 

 Atherinella panamensus, STEINDACHNER, Ichth. Beit., u, 35, 1875, Panama. 



361. LABIDESTHES, Cope. 



Labidesthes, COPE, Pfoc. Araer. Phil. Soc. Phila., 1870, 455, (siccitluin). 



This genus differs from Menidia chiefly in the prolongation of the jaws, 

 both of which are produced into a short depressed beak. The scales are 

 small, as in Leuresthes and Basilichthys, their edges entire. (Aa3i, a pair 

 of forceps ; e<7$oj,to eat.) 



1177. LABIDESTHES SICCULUS (Cope). 

 (BROOK SILVERSIDE ; SKIPJACK.) 



Head 4; depth 6; eye 3. D. IV-I, 11; A. I, 23; scales 75. Body 

 elongate, very slender, compressed. Head long, flattened above, narrow 



