434 DR. GUNTHBR ON THE FISHES OF CENTRAL AMERICA. 



85. Trachynotus kasciatus. (Plate LXIX. fig. 4.) 

 Trachymtus fasciatm, Gill^ Proc. Ac. Nat. Sc. Philad. 1863, p. 86. 

 — — glaucoides, Giinth. Proc. Zool. Soc. 1864, p. 150. 



D. 6|J 



20- ^^- 2 T8- 



Closely allied to T. glaucus, but with the body more elevated. The height of the 

 body is one-half of the total length (without caudal); the length of the head two- 

 sevenths. The maxillary extends to below the middle of the eye. Anterior dorsal and 

 anterior anal rays, and the caudal lobes, much prolonged, the length of the latter being 

 two-sevenths of the total. The ventral fin does not extend to the vent. Five narrow 

 blackish vertical bars across the lateral line. 



One specimen, 7 inches long, was obtained by Mr. Salvin at San Jose ; two others, 

 11 inches long, were obtained by Capt. Dow at Panama. 



Descr>2)tion. — This species has the body (without caudal) of a rhomboidal form, its 

 greatest height being between the last spine of the dorsal and the vent, and one-half of 

 the total length (without caudal) ; the upper profile between the dorsal and the snout is 

 oblique, feebly convex over the eye. The length of the head is contained thrice and one- 

 half in the total (without caudal). The diameter of the eye is rather more than the length 

 of the snout, and contained thrice and two-thirds in that of the head. The cleft of the 

 mouth is narrow ; the maxillary reaches nearly to the level of the centre of the diameter 

 of the eye ; its length is a little more than one-third of that of the head. The width of 

 the space between the eyes is more than one-third of the length of the head, or equal to 

 the distance from the tip of the snout to the centre of the eye. Praeoperculum with 

 the hinder margin straight, and at a right angle with the lower border, which is also 

 straight and parallel with the axis of the body. Operculum small, narrow, about two- 

 thirds as long as high ; the hinder border of the opercular apparatus is formed almost 

 entirely of the sub- and interoperculum ; it is rounded and membranaceous : the line of 

 the separation between the operculum and suboperculum is at right angles with that 

 between the sub- and interoperculum. There is a recumbent spine before the com- 

 mencement of the first dorsal, and in a line with the posterior part of the axil of the 

 pectoral ; the dorsal spines, seven in number, are short ; tlie first is minute, but erect, 

 and not attached by any apparent membrane to the second ; the others show a slight 

 progression in dimensions, and are united by a low membrane. The base of the soft 

 dorsal is not twice as long as that of the spinous ; the first two rays, which are the 

 longest, project considerably beyond any of the others, and are equal to half the length 

 of the body (without the caudal) ; the folloAving rays diminish very rapidly in length, 

 and from the eighth ray to the last the fin is scarcely higher than the spinous dorsal, 

 and its upper edge almost straight. The distance between the dorsal fin and the 

 caudal is equal to that between the anal and caudal. The anal fin is preceded by three 

 short spines about equal to the fourth, fifth, and sixth of the dorsal. The base of the 



