106 U. S. P. R. R EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



either side of the lower jaw being larger than the rest and situated more inwardly; and by the 

 presence of teeth on the palatine bones, which do not exist in the mackerels. 



PELAMYS LINEOLATA, Grd. 



SPEC. CHAR. Head sub-conical; gape of mouth somewhat oblique; jaws nearly even; posterior extremity of maxilJaries 

 extending to a vertical line drawn within the posterior rim of the orbit. Origin of anterior dorsal situated slightly in advance 

 of the base of the pectorals. Anterior margin of anal placed opposite the posterior margin of the second dorsal. Eight finlets 

 above the tail, and seven under it. Bluish black above, with longitudinal blackish streaks ; silvery on the sides, and yellowish 

 beneath. 



The only specimen of this species which has come under our observation as these sheets were 

 passing through the press, measures about eleven inches in total length. The body is most 

 gracefully elongated, rather slender, very much compressed, and sub-fusiform in its profile. 

 The greatest depth, taken at the insertion of the ventral fins, is contained six times in the total 

 length; the greatest thickness, at the same region, being about the half of the depth just 

 alluded to. 



The head constitutes about the half of the total length ; the gape of the mouth is somewhat 

 oblique upwards, the snout being sub-conical, and the jaws nearly even ; the lower one having 

 a tendency to project very slightly beyond the upper. The posterior extremity of the maxillar 

 bone, which is rounded, falls evenly with a vertical line drawn inwards of the posterior rim of 

 the orbit. The teeth are rather distant and more slender on the upper jaw than on the lower, 

 towards the apex of which two canine-like ones may be observed, one on either side, and some 

 what larger than the rest. The eye is moderate sized, sub-circular, its horizontal diameter 

 entering about six times in the length of the side of the head; twice in advance of its anterior 

 rim. The anterior nostril is very minute, situated midway between the apex of the rostrum 

 and the centre of the pupil; whilst the posterior one, an elongated, vertical, sub-crescentic split, 

 is placed somewhat in advance of the orbit, its sub-concave side towards the eye. The edge of 

 the opercular apparatus constitutes an even curve. 



The origin of the first dorsal fin takes place upon a vertical line which would pass somewhat 

 in advance of the base of the pectorals. It is highest anteriorly, diminishing gradually in 

 depth backwards. It is somewhat longer than the head, hence its length is a little more 

 than the fourth of the total length. A space of three-eighths of an inch exists between the 

 two dorsal fins. The second dorsal is sub- triangular, a little longer than high, and is followed 

 by eight finlets, the tip of the last of which reaching the base of the caudal fin. The aual, 

 somewhat smaller than the second dorsal, is sub-triangular also, its anterior margin being 

 situated nearly opposite the posterior margin of the latter mentioned fin. Seven finlets a little 

 larger than the dorsal ones may be seen under the peduncle of the tail. The caudal is slender, 

 its posterior margin having the shape of a very open crescent. The ventrals are moderate 

 sized, their anterior margin corresponding to a vertical line drawn immediately behind the base 

 of the pectorals. The pectorals themselves are rather short, sub-falciform and broad at the 

 base. 



Br. VII : VII ; D XVIII, 13 ; A 12 ; C 11, 1, 9, 8, 1, 12 ; V 1, 5 ; P 27. 



The scales, as already observed, are quite small and inconspicuous ; even those constituting 

 the thoracic corselet require something more than a superficial glance before their presence is 

 made obvious. The lateral line is somewhat undulated, although following a direct course from 

 the upper region of the thoracic arch to the peduncle of the tail. It is nearer the dorsal outline 



