416 DR. GUNTHER ON THE FISHES OF CENTRAL AMERICA. 
caudal), the length of the head thrice. The diameter of the eye equals the width of 
the interorbital space, is one-fifth of the length of the head, and two-thirds of the 
extent of the snout. Snout produced; cleft of the mouth wide; the maxillary extend- 
ing beyond the front margin of the eye. Praoperculum with the hind margin vertical 
and finely serrated. The spinous and soft portions of the dorsal fin are separated by a 
notch; dorsal spines moderately strong, the fourth being the longest, its length being 
contained twice and three-fourths in that of the head. Second anal spine exceedingly 
strong, more than half as long as the head. Caudal fin slightly emarginate ; pectorals 
terminating at some distance before the vent. Scales ctenoid. _Coloration uniform. 
This species is known from a single example (size not stated) from the Rio Bayano 
(Panama). 
27. PRISTIPOMA MACRACANTHUM. (PI. LXIV. fig. 1.) 
Ginth. Proc. Zool. Soc. 1864, p. 146. 
D.11|5. A. 3/8. L. lat, 47. L. transy. 6/13. 
The height of the body equals the length of the head, and is one-third of the total 
(without caudal). The diameter of the eye equals the width of the interorbital space, 
and is two-thirds, or somewhat less than two-thirds, of the extent of the snout. Hind 
margin of the anterior nostril with a broad flap. Snout somewhat produced; the 
maxillary does not extend to below the anterior margin of the eye. Praoperculum 
with the hind margin rather concave, and with stronger teeth at the angle, which is 
rounded. ‘The spinous and soft portions of the dorsal fin are separated by a deep 
notch, the spine of the soft portion being much longer than the preceding, which is 
somewhat longer than the second. Dorsal and anal spines exceedingly strong; the 
fourth dorsal spine is the longest, its length being contained twice and a third in that 
of the head. The second anal spine much longer and stronger than the third, and even 
than the fourth dorsal spine. Candal fin truncated. ach soft ray of the vertical fins 
is accompanied by a series of minute scales. The pectoral fin extends to the vent. 
Scales smooth. Silvery, with several very indistinct dark cross bands on the back, 
which appear to be arranged as in P. leuciscus. 
Two specimens, 11 and 14 inches long, were collected by Mr. Salvin at Chiapam. 
29. Pristipoma Leuciscus. (Pl. LXVI. fig. 3.) 
Gimth. Proc. Zool. Soc. 1864, p. 147. 
De i A, 3/f-8, -L. lat. dil; Wustransy. seh 
The height of the body is contained thrice or thrice and a third in the total length 
(without caudal), the length of the head thrice and a fourth. The diameter of the eye 
is equal to, or more than, the width of the interorbital space, but is less than the extent 
of the snout. The maxillary does not quite extend backwards to the vertical from the 
anterior margin of the orbit. Preeoperculum finely serrated behind, with the angle 
