108 
SCANDINAVIAN FISHES. 
THE FRIGATE-MACKEREL OR PLAIN BONITO. 
AUXIS THAZARD. 
Fig. 31. 
Back glossy indigo or grayish blue, with irregular , dark-blue spots and stripes, which sometimes vanish: ventral 
sides silvery. 
Fig. 31. 
Frigate-Mackerel (A'uxis thcizard), from the south of the Cattegat. Specimen belonging to Lund Museum. 
V 3 natural size. 
R. br. 7; D. 10 1. Ml- 2 /VIII ]. IX; A. 2 — ’’ /VII: 
’ ' 9 1. 10' 10 1. IF 
P. 22 1. 23; V. V 5 ; C. a x+19+x. 
Syn. Scomber thazard, Lacep., Hist. Nat. Poiss., vol. Ill, p. 9; 
Cuv., Val. (Auxis = Scomber tazo, Commerson), Hist. Nat. 
Poiss., vol. VIII, p. 146; Br. -Goode (Auxis), Fish. Industr. 
U. S., part. 1 , p. 305, tab. 92. 
Scomber Rochei, Risso, Ichth. Nice , p. 165; Id. ( Thynnvs 
roclieanus ), Eur. Mer., vol. 3, p. 417; Gthr, (Auxis), 
Cat. Brit. Mus., Fish., vol. II, p. 369; Nilss., Ofvers. 
Vet.-Akad. Forh. 1863, p. 500, tab. VI, Day, Fish. G:t 
Brit. Irel., part. I, p, 104, tab. XXXIX, fig. 1 et 1 a ; 
Lillj., Sv., Norg. Fiskar, vol. I, p. 280. 
Scomber bisus, Raein., Caratt., p. 45, tab. 2, fig. 1. 
Auxis vulgaris, Cuv., Val., 1. c., p. 139, tab. 211. 
Orcynus thynnns, Be. -Goode, Fish. Industr., 1. c., tab. 96. 
Obs. Though Cuvier distinguished between Commerson’s Scomber 
taso and the Frigate-Mackerel described by Risso and Rafinesque, he per- 
sonally acknowledged that he could discover no other difference than 
the absence in taso of the dark markings on the back, which he 
sometimes, however, could not find in the Frigate-Mackerel (1. c., p. 
145), and a small, oval, blue-black spot under the eye, which, on 
the contrary, he assumed to mark taso. Both Day and Brown-Goode, 
however, have amalgamated the two species; arid, as we already know 
from Gunther’s explanation of Bleeker’s Auxis thynnoides as a syno- 
nym for Auxis Rochei that the Frigate-Mackerel has a place in the 
fauna of the East Indian Archipelago, there should be no doubt as 
to the meaning of Lacepede’s Scomber thazard, a name which we 
must thus recognise as the original designation of the species. 
The form of body of the Frigate-Mackerel changes 
so much with age that we have in it an admirable 
example of the transition from the Mackerel-type to 
that of the Tunny. During youth the greatest depth 
of the body is not more than 1 / 6 of the length; but 
in old specimens it rises as high as ] /4- With respect to 
the great distance between the two dorsal fins, which may 
be more than twice the length of the base of the first 
dorsal, the Frigate-Mackerel, as we have already stated, 
is really a Mackerel; but by the situation of the second 
dorsal fin, which lies either completely, or for the grea- 
ter part, in front of the perpendicular from the begin- 
ning of the anal, it. ranges itself with the Tunnies. 
According to Nilsson’s measurements the situa- 
tions of these three fins are as follows: 
Distance between the first dorsal and (he tip of the snout in % of 
the length of the body, 32.8; 
Distance between the second dorsal and the tip of the snout in % of 
the length of the body, 68.2; 
Distance between tbe anal and the tip of the snout in % of the 
length of the body, 74.1. 
“ x-r-21 +x according to Moreau, x 4- 14+ x according to Lilljeborg. 
& Blbeker’s Auxis tapeinosoma from Japan is also, according to Steindaci-iner (Denkschr. Math. Naturw. Cl. Akad. Wiss. Wien, Bd. 
XLIX, p. 180), identical with Auxis Rochei. 
