DR. GUNTHER ON THE FISHES OF CENTRAL AMERICA, 423 
line ; it is short, one-eighth of the total length, and does not quite reach the vent; its 
spine is about 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 blackish at their margins. Operculum black. 
52. POLYNEMUS APPROXIMANS. 
Polynemus approximans, Lay & Benn. in Beechey’s Voy. Zool. Fish. p. 57. 
Trichidion approximans, Gill, Proc. Ac. Nat. Se. Philad. 1863, p. 169. 
D.7\5. Aj L. lat. 60. 
15 
Six pectoral appendages, the longest of which reaches to the commencement of the 
anal fin. The length of the caudal lobes is rather more than one-fourth of the total 
length, Pectoral fins blackish. 
Description.—This fish is moderately elongate in form; its greatest height, which 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 length. The snout is 
produced, obtusely conical, and shorter than the diameter of the eye, which 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 behind the orbit, 
but the length of the bone is only two-fifths of that of the head. The posterior margin 
of the preoperculum is armed with a distinct serrature, and one or two more distinct 
teeth above the projecting membranaceous lobe of the angle. ‘The 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 yentral fins. The 
first spine is minute, the second shorter than the third, which is the longest, and con- 
tained about once and one-third in the length of the head; the fourth is longer than the 
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 high as the spinous dorsal, more than 
twice as long as the hindmost rays. The distance between this fin and the caudal is 
