232 Dll. A. GUNTHER ON NEW AMERICAN FISHES. [Mar. 26, 



base ; lower parts with numerous similar but more distinct white 

 dots. 



This beautiful species, which I have named after Mr. Ford, is 

 probably from Surinam. Four male specimens, the largest 9 inches 

 long, were obtained from the collection of Dr. van Lidth de 

 Jeude. 



Ch^etostomus depressus. 



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



Head and trunk much depressed and flattened. The length 

 of the head is rather more than one-third of the total (without 

 caudal) ; the diameter of the eye is one-fifth of the length of the 

 head, and two-thirds of the width of the interorbital space. The 

 margin of the snout is covered with short bristles ; interoperculum 

 with a bundle of about eight similar bristles, the longest being only 

 half as long as the eye. The lower margin of the opercle slightly 

 serrated. The lower side of the head, thorax, and belly entirely 

 naked. Dorsal fin rather higher than long, the first ray being 

 shorter than the head ; the length of its base is nearly equal to its 

 distance from the caudal ; there are six scutes between the two 

 dorsal fins. Caudal fin obliquely truncated, the lower rays being 

 much longer than the upper. Pectoral spine extending to the 

 second third of the ventral, and rather rough ; ventral fin extending 

 to the end of the anal. Eleven scutes between the anal and caudal 

 fins. Scutes with numerous striae, each stria composed of numerous 

 very small spines. Posthumeral ridge obtuse. Brown, each scute 

 with several round very small whitish dots ; dorsal and caudal rays 

 with a series of similar dots, the interradial membrane being im- 

 maculate. 



This species is also probably from Surinam ; one male specimen, 

 6 inches long, has been obtained from the collection of Dr. van 

 Lidth de Jeude. 



This species is allied to Pleeostomus barbatus and P. guttatus. 

 We have received a very complete series of the former species from 

 the same collection, and I find that the long bristles on the margin 

 of the snout and the interoperculum form a sexual character and 

 are peculiar to the male. In the female they are very short, and 

 sometimes scarcely developed. Both these species might be re- 

 ferred, with greater propriety, to Chcetostomns. 



Ch.^tostomus megacephalus. 



D. 1/7. A. 5. P. 1/6. L. lat. 23. 



Head but slightly depressed, rather longer than broad, its length 

 being more than one-third of the total {without caudal); a very 

 obtuse ridge runs from the upper angle of the orbit to below the 

 nostril ; occiput flat ; interorbital space with a pair of shallow 

 grooves. The horizontal diameter of the orbit is more than one- 

 half of the width of the interorbital space, and about one-fifth of 

 the length of the head. Margin of the snout granulated, without 



