1868.] DR. A. GUNTHER ON NEW AMERICAN FISHES. 233 



bristles ; interoperculum with a bundle of about twenty setiform 

 spines, the longest of which are about one-fourth of the length of 

 the head, and extend backwards to the root of the pectoral fiu. 

 Thorax and belly entirely naked. Dorsal fin rather higher than 

 long, the length of its anterior rays being three-fourths of that of 

 the head ; the length of its base equals its distance from the root of 

 the caudal. There are six scutes between the two dorsal fins. 

 Caudal fin forked, the lower lobe being the more developed. The 

 pectoral spine extends to the second third of the ventral ; the 

 ventral fin to the middle of the anal. Twelve scutes between the 

 anal and caudal fins. Scutes of the body without keels, but with 

 vertical series of spines, the anterior scutes with one series only, the 

 middle with two, and the posterior with three or more. Posthumeral 

 ridge indistinct. Blackish brown ; head and body with numerous 

 indistinct round yellowish spots, each about as large as the pupil ; 

 each dorsal ray with a series of round whitish spots, the black 

 ground-colour forming a network on the fin. 



One male specimen, 6 inches long, has been obtained from the 

 collection of Dr. van Lidth de Jeude. It is probably from 

 Surinam. 



Ch^tostomus dentex. 



D. 1/7. A. 4. P. 1/6. L. lat. 23. 



Head depressed, rather longer than broad, its length being some- 

 what more than one-third of the total (without caudal). A very 

 distinct short ridge runs from the upper angle of the orbit to below 

 the nostril. Interorbital space and occiput flat, the orbital margin 

 being slightly elevated. Eye rather small, its horizontal diameter 

 being one-half of the width of the interorbital space. Margin of 

 the snout rough, like the surface of the head, but without bristles. 

 Ititeroi)e7'culum with a bundle of about ten straight setiform spines, 

 the longest of which is as long as the eye. Thorax and belly nearly 

 entirely naked, there being only a few granulations behind the 

 throat. Teeth comparatively large, ivith the apex dilated, scarcely 

 lobed; there are about six on each side in the upper jaw, and three 

 in the lower. Dorsal fin higher than long, but its anterior ray is 

 shorter than the head ; the length of its base is less than its distance 

 from the caudal ; there are seven scutes between the two dorsal fins. 

 Caudal fin forked, the lower lobe being much longer than the upper. 

 The pectoral spine extends to the second fourth of the ventral ; the 

 ventral fin beyond the anal. Eleven scutes between the anal and 

 caudal. Scutes not keeled, but covered with strong spines. Uni- 

 tbrm greyish brown. 



One example, 3^ inches long, was found by Mr. Bartlett at 

 Xeberos. 



.\CANTHICUS HYSTRIX, Spix. 



The figure given by Spix is not good ; but the species may be 

 readily recognized from it. Mr. Bartlett obtained a splendid ex- 



