336 



U. S. p. R R. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



is large and circular ; its diameter entering about three times in the length of the side of head. 

 The snout is abbreviated, the apex of the lower jaw projecting considerably in advance of the 

 orbit, and the posterior extremity of the maxillar bone extending to the gill apertures. 

 The dorsal fin is sub-triangular, anteriorly higher than long, its origin being nearer the tip of 

 the snout than the extremity of the caudal fin. The latter is furcated and nearly equal to the 

 head in length. The base of the anal fin is almost twice as long as that of the dorsal, and its 

 anterior margin situated opposite the middle region of the latter ; its base entering about five 

 times in the total length. The ventrals are small and short, posteriorly sub-truncated ; their 

 extremities reaching the vent, which is placed midway between the origin of the anal fin and 

 the insertion of the ventrals, being just opposite the anterior margin of the dorsal fin. The 

 pectorals are elongated, slender, and sub-lanceolated ; their posterior extremities being but at a 

 short distance from the insertion of the ventrals. 



D 2, 13 ; A 2, 22 + 1 ; C 7, 1, 8, 8, 1, 6 ; V 5 ; P 12. 



The few scales which still remain scattered, are very large and deeper than long. The 

 ground color is yellowish ; a silvery band, about a tenth of an inch or slightly more in width, 

 occupies the middle of the flanks from the head to the base of the caudal fin. 



List of specimens. 



4. ENGKAULIS COMPEESSUS, Grd. 



Spec Char.— Body very much compressed, rather short and deep. Head consiitutiiig about the fifth of the total length, 

 Snout abbreviated. Posterior extremity of maxillar bane extending to llie intcroperclo. Eye large and sub-circular; its 

 diameter entering about three times and e half in the length of the side of the head. Anterior margin of dorsal fin nearly 

 equidistant belwccn tlic tip of the snout and the fork of the caudal fin. Base of anal fin entering three times in the length, the 

 caudal fin exchided. The latter is somewhat shorter than the head. Vent situated near the origin of the anal and opposite 

 the anterior margin of the dorsal fin. Ventrals quite small, nearly reaching the vent. Pectorals broad and well developed, 

 extending as far as tlie insertion of the ventrals. Yellowish brown, with a silvery streak along the middle of the flanks. 



This species, in its general appearance, so closely resembles E. ddicatissirmis, that on a 

 superficial inspection we had supposed it was identical with it. On a closer examination we 

 became very soon acquainted with difierential characters so striking, that nothing after that 

 was easier than to tell the differences between tlie two species. 



The greatest length of the specimens before us is scarcely four inches ; the greatest depth 

 being equal to the length of the head, hence enters about five times in the total length. The 

 snout is sub-conical and quite abbreviated. The dorsal fin is much higher than long, and 

 sub-triangular in shape. The anal fin is very long; its anterior third constituting a triangular 

 figure, whilst its remaining portion is very low. Its origin is placed opposite the middle of the 

 dorsal ; the vent being quite near to it. The ventrals are rather small, posteriorly sub-truncated, 

 and when directed backwards their extremities approximate the vent. The pectorals are well 



