SC0mbridae
Thunnu3 thynmw {_Lll—"îliiëë
38
Bluefin tuna
MAGURO
N.olf.
9“‘
'
bulb.olf.—————
'
\
bulb.olf.
_
\\
__
_
_
fis.en
_
flS.€d.
_
iob.0lf.
\
ui_yp.
_
hyp0$
__
_
hypos.
N.3
/
3,_________@
_
“
lob.mf
—
_
”
_
…
N.7.
-
’/
““
N'7'
.
N 8
sac.vas.
“°…—————@
'
'
-
,
,
emin.gran.
_
emin.g.an.——/
//
‘
'“"@
.
‘"
acu.lat.a.
__
//
»
-
-
c.cbl.
crust.cbl.
\N
9
10
N.9.+10.
\
med.ob.
/
med.sp
med.sp—_
5mm
lateral
ventral
-
dorsal
W_…m……__.__
Descriptive notes :
“ËÎËlÈ"ËÊlCËËLÎU%.
Adults attain about 250 cm in body length.
Body elongate and spindle—shaped with conical head ‘and
(/]\HÈÎ)
%Ël…
slender peduncle.
Mouth widely cleft; nostrils
Hi —
LK».
well-developed.
Small conical teeth in a single series in both jaws.
Body color leaden black, ventral surface, silver-white.
Swim day and night near the surface and mid-waters of
ocean.
Extent of migration wide.
Swimming movement very quick.
Swim mostlyin schools.
Eat day and night mackerels, cuttlefish, flying fish,
sardines, anchovy and other small fishes possibly located
by means of sight and auditory and olfactory senses.
The fish are of the Temperate Zone, but found in tropical
waters as well.
Bulbus olfactorius closely attached underneath lobus
olfactorius.
Lobus olfactorius somewhat large with a dorsal
tubercle.
Corpus cerebelli enormously large covering
,
dorsally optio lobes and medulla oblongata.
Hypophysis considerably large.
Optic lobe welldeveloped
_
with a deep groove.
Corpus cerebelli is divided by several
-
transverse fissures.
Eminentia granularis very
well-developed.
Acoustico-lateral lobe well-developed.
102—103