DE. GUNTHER ON THE FISHES OF CENTRAL AMERICA. 475 



caudal) ; the length of the head five times. The lower jaw is slightly shorter than the 

 upper. Interorbital space flat, its width being less than twice the width of the eye. 

 Dorsal fin with the spine very feeble, somewhat higher than long. Pectoral fin rather 

 short, as long as the head, without snout ; its spine about double the length of the 

 humeral spine. Porus axillaris distinct. Ventral rather longer than the pectoral. 

 Anal fin with the base longer than that of the dorsal ; its rays do not extend nearly to 

 the end of the adipose fin if laid backwards. Caudal cleft to the base ; its upper lobe 

 less rounded and narrower than the lower one, which is one-seventh of the total length. 

 Coloration uniform, dorsal tin with a whitish cross band. 



One specimen, 9 inches long, was obtained by C^apt. Dow in the Lake of Managua. 



214. AeIUS ASSIMILIS. 



Giinth. Fish. v. p. liG. 



D. 1/7. A. 19. P. 1/10. 



The height of the body is contained four times and two-thirds in the total lengtli 

 (without caudal), the length of the head thrice and three-fifths ; head much broader 

 than high, its greatest width being three-fourths of its length. Eyes rather small, 

 situated nearer to the end of the snout than to that of the operculum ; the length of 

 the snout is three-tifths of the width of the interorbital space. The median lomiitiidinol 

 fonticulus on the upper side of the head does not extend to the base of the occipital pro- 

 cess. Teeth on the vomer but slightly separated in the middle, forming 

 a pair of oblong transverse patches, which are confluent with those on 

 the palatine bones ; the latter are short, club-shaped. The band of 

 intermaxillary teeth is five times as broad as long. All the teeth villi- 

 form. The maxillary barbels extend nearly to the end of the head ; the 

 lensth of the outer ones of the mandible is one-half or two-thirds of that of the head. 

 Crown of the head granular, the granulations being arranged in radiating streaks. 

 Occipital process broader than long, triangular, with its hinder end concave. The 

 basal bone of the dorsal spine of moderate size, crescent-shaped. Dorsal spine of 

 moderate strength, more than half as long as the head, granulated in front and slightly 

 " serrated behind ; the first soft ray is longer than the spine and as high as the body. 

 Adipose fin shorter than the dorsal. Caudal deeply forked, with the upper lobe 

 longest, its length being contained five times and a half in the total. Pectoral spine 

 serrated along its inner edge and on the extremity of the outer edge. N'entral fin 

 shorter than pectoral. Sides of the body silvery ; vertical fins greyish ; basal half of 

 the inner side of the paired fins black. 



One example, \?> inches long, was obtained by Messrs. Godnian and Salvin in the 

 Lake of Yzabal. 



Ilcxnnematichthys hi/menorrhinos, Bleek. Versl. & Mededeel. Akad."^^'etensch. Amsterd. 

 1862, xiv. p. ?>n, appears to be closely allied to the above species; and we should not 



3 T 2 



