104 
SCANDINAVIAN FIS H E S . 
below the lateral line to the beginning of the first 
dorsal fin, and a third, smaller sinus, extending to a 
perpendicular from the middle of the pectoral fin's, may 
be distinguished below this. The hind margin of the 
preoperculum is fairly straight, but the lower margin 
is arcuate. The hind margin of the gill-opening runs 
parallel to the margin of the preoperculum. The nos- 
trils resemble those of the other Scombroids; the pos- 
terior being a perpendicular slit just in front of the 
eye, the anterior a round opening on a level with the 
upper margin of the eye and about half-way between 
the tip of the snout and the hind margin of the eye. 
The jaw teeth are subulate and large, but scattered. 
In the lower jaw, however, their height is greater than 
the distance between them, and about V 2 the diameter 
of the pupil. According to Collett, the palatine and 
vomerine teeth are small; and on the tongue there are 
two patches of villiform teeth. 
The internal organs of this species are little known, 
but in Orcynopsis nuda, which at least resembles it 
closely, Klunzinger (1. c.) found the pyloric appendages 
united into a gland, as Cuvier has stated is the case 
in the Tunny. 
The Plain Pelamis is one of the rarest of fishes; 
and only a few specimens from the Mediterranean and 
three from the Cattegat and Christiania Fjord are known. 
Two of the latter were taken off Xsesoen, between 6 
and 7 miles from Christiania, at the end of August, 
1876, and another was caught in the same year off 
Kongback in Sfromstad Fjord and preserved by Dr. 
C. Cederstrom, by whom it was stuffed and sent to 
the Royal Museum. 
Of its habits we only know that it follows the 
herring-shoals — Collett found the belly full of her- 
ring-fry — and as, in contrast to the other Scombroids, 
it is so seldom observed, it is highly probable that it 
generally keeps to deep or fairly deep water. Filippi 
and V erany state that its flesh is good and wholesome. 
According to Moreau, specimens from 7 to 7 1 / 2 dm. 
in length weigh 3 kgrm. 
Subgenus SARDA. 
Body behind the corslet covered with small scales. Height of the anal fin generally under 8 {fir. 5 to 7) % of 
the length, of the body a . Length of the ventral fins about, equal to or greater than the height of the anal fin and 
at least 2 / 3 (fr. 67 % to 74 %) of the length of the pectoral. Length of the head , as well as the distance between 
the tip of the snout and the first dorsal fin , at least 1 / i (fr. 25 % to 27 %) of the length of the body. Length of 
the pectoral fins less than half (fr. 41 % to 43 %) the length of the head , of which the length of the ventral fins 
is more than (fr. 28 % to 31 %). Palatine bones with teeth , but the vomer toothless. 
It was Cuvier who first 6 introduced this subgenus, | the Greeks, however, according to Cuvier, originally 
the name of which he afterwards'" changed to Pelamys , i meant the salted flesh of the Tunny, 
while Gill' 6 has adopted the older name, which among 
° According to Lutken, in the largest of the specimens of Sarda chiliensis examined by him the height of the anal fin was 9‘8 % of 
the length of the body, and the length of the pectoral fins 55'5 °/> of the length of the head. This exception, as well as Steindachner’s 
statement as to the length of the ventral fins in the same species, indicates a condition of 'development which renders our generic and sub- 
generic definitions of the Scombroids merely expressions of more or less fixed stages in a common development. Strictly speaking, too, only 
the characters which we have adopted above (pp. 91 and 92) in the scheme for the division of the family, are constant; but the others show 
partly the different directions of development and partly the stages at which the forms, as far as we know them, have generally stopped. 
b Regn. Anim., ed. 2, vol. II, p. 199. 
c Cuv., Val., 1. c., pp. 138 and 149. 
d Proc. Acad. Nat. Sc. Philad., 18G2, p. 125. 
