DR. GUNTHER ON THE FISHES OF CENTRAL AMERICA. 451 
161. Heros MACRACANTHUS. 
Giinth. Proe. Zool. Soc. 1864, p. 153. 
Dita A-gap L. lat. 31. L. transv. 7. 
The lower lip is interrupted in the middle. The height of the body is two-thirds of 
the total length (without caudal) in adult specimens, but only one-half in immature; 
the length of the head is one-third of the total. Upper profile of the head very steep, 
not concave. Scales on the cheek in five series. ‘The first dorsal spine is a little before 
the vertical from the upper end of the gill-opening. Dorsal and anal spines strong, the 
tenth of the dorsal fin being two-fifths of the length of the head. Pectoral as long as 
the head. Dark greenish, many scales with a pearl-coloured spot in the upper or lower 
angle. Vertical and ventral fins black. 
About a dozen specimens, from 3 to 9 inches long, were collected by Mr. Salvin at 
Chiapam and Huamuchal. 
Description.—The height of the body is two-thirds of the total length (without 
caudal), and nearly one-half of the entire length of the fish. The length of the head 
is one-third, or slightly more than one-third of the total (without caudal). Head 
rather higher than long, the nape convex, but the upper profile showing a slight 
concavity above the snout. The snout is of rather considerable extent, the height of 
the preorbital being one-half more than the width of the orbit. The cleft of the 
mouth is slightly oblique; the preorbital almost covering the posterior end of the 
maxillary, which does not attain the line of the front margin of the eye. Jaws rather 
protractile, armed with a broad band of villiform teeth, those of the outer series being 
enlarged. Interorbital space convex, nearly twice the width of the orbit. Eye some- 
what nearer to the end of the operculum than to that of the snout. Base of soft 
dorsal and anal with a few small scales. Dorsal spines strong; the twelfth is a little 
less than one-half of the length of the head in adult specimens; the fifteenth is the 
longest, and more than half the length of the head. Soft dorsal and anal much 
elevated; the middle rays produced; caudal rounded. Pectoral rounded, about as 
long as the head. First ventral ray slightly prolonged. The free portion of the tail 
is nearly twice as deep as long. Greenish or brownish olive; fins black; a more or 
less distinct black spot on the root of the caudal fin, above the lateral line. Immature 
specimens with six very indistinct dark cross bands, the third of which has a blackish 
blotch below the lateral line; an indistinct blackish spot at the root of the caudal fin. 
162. Heros spiturus. (Plate LX XIII. fig. 1.) 
Giinth. Fish. iv. p. 289. 
D. io" A. . L. lat. 29. L. transv. = 
The fold of the lower lip is interrupted in the middle; four series of scales on the 
cheek. The height of the body is one-half of the total length (without caudal), the 
3Q2 
