DR. GUNTHER ON THE FISHES OF CENTRAL AMERICA. 479 
old specimens. ‘The origin of the dorsal fin is nearer to the root of the caudal than to 
the extremity of the snout; its hinder rays are vertically above the anterior anal rays. 
The free portion of the tail is considerably longer than 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 16 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. ANACYRTUS GUATEMALENSIS. (Plate LX. XXII. fig. 4.) 
Anacyrtus (Reboides) guatemalensis, Giinth. Fish. vy. p. 347. 
D. 11. A. dl. 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 process 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, Exocatus cALLoprerus. (Plate LX XXIII.) 
Ginth. 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-fourth. The depth of the head equals the distance 
between the extremity of the snout and the hind margin of the preoperculum, 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 
