FISHES OF SINALOA. 419 



not falcate, inserted high, i^ in head, 6 in body, reach- 

 ing to the middle of the small ventral. Belly not espe- 

 cially compressed, not cultrate. First dorsal very small, 

 slightly nearer snout than base of caudal, over first ray of 

 anal; last ray of dorsal much before last of anal. Anal 

 very long, somewhat elevated in front, its base 3 times in 

 length of body. Soft dorsal and anal scaleless. 



Color translucent green, ver}^ pale; back, lips and bases 

 of vertical fins faintly dotted; lateral band very broad 

 and highly silvery, about two-thirds as broad as eye ; 

 lower fins pale; air-bladder not visible through the flesh. 



One specimen, 2^ inches long. 



63. Thyrina evermanni Jordan & Culver, n. g. and n. sp. 

 Plate xxxiii. 



Common in the estuary. In this species the structure 

 of the mouth is exactly as in Thyrina crystallina. It 

 differs from that seen in Menidia only in having the upper 

 jaw shorter. It is apparently closely related to the genus 

 Atherinella of Steindachner, but it has not the toothed 

 scales of the type of that genus, Atherinella panamensis. 

 The other characters of Atherinella — the great length 

 of the pectoral fin, the great compression of the breast 

 and the long anal fin — are shared by this species which we 

 have made the type of a new genus, Thyrina. The name 

 {dbfii^, window) refers to the translucent sides. Both 

 Eurystole and Thyrina are intermediate between Menidia 

 and Atherinella. 



TJiyrina evermanni differs from Thyrina c?ystallina in 

 the longer anal, the more falcate pectoral, the smaller 

 scales, more compressed breast and the absence of black 

 on the fins. 



Head 4^; depth 4^ to 5 ; dorsal iv, i, 7; anal I, 

 23 to 1, 25; scales 36-9; eye 2^3 in head; snout 3I in 

 head; maxillary 3I in head; lower jaw 2^ in head; 



