DR. GttNTHER ON THE FISHES OF CENTRAL AMERICA. 479 



old specimens. The origin of the dorsal fin is nearer to tlie root of the caudal than to 

 the exti'emity of the snout ; its hinder rays are vertically above the anterior anal rays. 

 The free portion of the tail is consideiably longer tlian high. Caudal deeply forked. 

 The pectoral extends to, or nearly to, or a little beyond, the ventral. Silvery, sometimes 

 with a reddish hue ; a part of the scales have sometimes a black margin, or are spotted 

 with black ; humeral part of the gill-opening black ; sometimes a black spot at the root 

 of the caudal. Anal fin generally with a black margin. 



Specimens, up to 10 inches in length, were collected by Messrs. Salvin and Godman in 

 the Rio Motagua and Usumacinta, and at Yzabal. The species occurs also in Ecuador. 



240. An.\cyrtus guatemalensis. (Plate LXXXII. fig. 4.) 

 Anacyrhis [Roeboides] guatemulensis, Giinth. Fish. v. p. 347. 



D. 11. A. 51. V. 8. L. lat. 80. L. transv. 19/22. 



Upper and lower jaw anteriorly on each side with a short, conical, tooth-like process 

 directed forwards ; teeth in the intermaxillary, maxillary, and mandible in a single, 

 rather irregular series ; no canine teeth in the upper jaw, those in the lower small and 

 short. Back elevated, the upper profile of the head and nape forming an S-shaped 

 curve. The height of the body is contained twice and three-fourths in the total length 

 (without caudal), the length of the head four times. The lower jaw is rather shorter 

 than the upper ; the maxillary extends to the vertical from the centre of the eye. The 

 width of the interorbital space is a little less than the diameter of the eye, which is 

 two-sevenths of the length of the head. The humeral proce.ss in front of the pectoral 

 terminates in a point anteriorly and posteriorly. The origin of the dorsal fin is a little 

 nearer to the extremity of the snout than to the root of the caudal, above the fifth or 

 sixth anal ray ; caudal deeply forked ; the ventral is inserted below the middle of the 

 pectoral, which extends nearly to the origin of the anal. Light reddish olive with a 

 silvery lateral band. 



Specimens, up to 6 inches in length, were collected by Mr. Salvin at Huamuchal, 

 and in the Chagres River. 



244. ExocffiTus CALLOPTERUS. (Plate LXXXIII.) 



Gunth. Fish. vi. p. 292. 



D. 11-12. A. 8. L. lat. 46. 



Body stout, its height being one-fifth of the total length (without caudal), the length of 

 the head being somewhat less than one-fouvth. The depth of the head equals the distance 

 between the extremity of the snout and the hind margin of the prseoperculum, Snout 

 obtuse and depressed, three-fifths of the length of the diameter of the eye, which is 

 one-third of the length of the head, and less than the width of the interorbital space, 

 which is slightly concave. The pectoral fin extends to the end of the dorsal. Ventral 



