DR. GUNTHER ON THE FISHES OF CENTRAL AMERICA. 423 



line ; it is short, one-eighth of the total lengtli, and does not quite reach the vent ; its 

 spine is ahout one-half the length of the adjacent ray. The scales are of moderate size, 

 longer than high, and have the posterior margin minutely crenulated. Lateral line 

 straight, very slightly bifurcated between the lobes of the caudal. The teeth are 

 minute and villiform, those of the vomer form a rounded or nearly square patch ; the 

 band on the palatines cuneiform and elongated, broadest anteriorly. The body is 

 uniform silvery, greenish grey, darker on the back ; the fins are minutely dotted with 

 black, the dorsals becoming blackisli at their margins. Operculum black. 



•32. TOLY-NEMUS APPROXI.\IANS. 

 Pulyneiiius upproa^imans, Lay & Bciiu. in Beechey's Voy. Zool. Fisli. p. 57. 

 Trichidion approximans, (iill, Proc. Ac. Nat. Sc. Philad. 18(;.'5, p. 1G9. 



I). 7 I ^3. A. jl. T. lat. GO. 



Six pectoral appendages, the longest of which reaches to the commencement of the 

 anal fin. The length of the caudal lobes is rather more tlian one-fourth of the total 

 length. Pectoral fins blackisli. 



Description. — This fish is moderately elongate in form; its greatest height, whicli is 

 between the root of the second dorsal and anal fins, is contained four times and one-third 

 in the total length with the caudal, and thrice and one-fourth in the same without 

 caudal. The tail is compressed, its height above the end of the anal being contained 

 seven times and one-third in the total length. The head is much longer than high ; its 

 length is about four times and a half in the total with, and thrice and a half without 

 caudal; its width between the eyes is nearly one fourth of its lengtli. Tlie snout is 

 produced, obtusely conical, and sliorter than the diameter of the eye, whicli is one-fifth 

 of the length of the head. The cleft of the mouth is situated at the inferior side of 

 the head, as usual ; it is wide ; the maxillary reaching considerably beliind the orbit, 

 but the length of the bone is only two-fifths of that of the head. The posterior margin 

 of the praeoperculum is armed with a distinct serrature, and one or two more distinct 

 teeth above the projecting membranaceous lobe of the angle. 'l"he posterior extremity 

 of the opercular apparatus is angular, membranaceous, and formed by the operculum 

 and suboperculum. The origin of the first dorsal is opposite to the eighth scale of the 

 lateral line, and in the vertical between the roots of the pectoral and ventral fins. The 

 first spine is minute, the second shorter than the third, whicli is the longest, and con- 

 tained about once and one-third in the length of the head ; the fourth is longer tlian tlie 

 second ; and the subsequent spines rapidly decrease in length, rendering the upper 

 margin almost vertical. There is a series of scales behind each spine almost to the top. 

 The distance between the two dorsals is more than the length of the base of the 

 second, which is entirely covered with scales and has the upper margin emarginate ; 

 the first and second rays are the longest, not so higli as the spinous dorsal, more tlian 

 twice as long as the hindmost ravs. The distance between this fin and the caudal is 



