FRIGATE-MACKEREL. 



109 



II' we compare these nieasiireiiients with the aI)ove- 

 ineritioned figures of Day or Ukown-Goodk, which 

 represent young specimens, we shall find that tlie cor- 

 i-esponding proportions are, respectively, 2!) — .^0, 60 — 

 ii2, and 66 — (t8. Hence we conclude that in the Fri- 

 gate-Mackerel, as ill tiic ^Mackerels, the length of the 

 preahdominal i-egioii, as well as its height, increases 

 with age, a state of things directly opposed to that 

 we have observed above in the Tunnies, whose groAvth 

 consists, to a, great extent, in the elongation of tlie 

 caudal region, and in which the dorsal and anal tins 

 seem, in relation to the length of the bod}', to apj)roach 

 tlie ti]> of tlic snout as they grow older. 



Ill the Frigate-Mackerel the form of the head is 

 especially marked by the short, but pointed, snout and 

 the sharply curved (almost elliptic) hind margin of the 

 preoperculum. The length of the head about ^4 of 

 that of the body. The eyes fairly small in proportion 

 to the length of the head (lietween 1!) and 17 %), but 

 large in jiroportion to the length of the snout, of 

 wiiich they mea.sure 75 %. Of the breadth of the iii- 

 terorbital space they measure 60 %. The gape com- 

 paratively small. When the mouth is closed, a great 

 portion, even of the back part, of the upper jaw-bone 

 is covered by the preorbital bone and its dermal Hap; 

 1)1 it the lower posterior corner and a part of the hind 

 margin of the jaw-bone falls into a cavity in the ex- 

 ternal mai-gin of the loAver jaw. The margin of the 

 gill-co\ers ciliated. The corslet well defined, with a 

 depression, as usual, on each side for the pectoral fins 

 and one common to the ventral fins. The uppermost 

 of its points, which are directed backwards, extends 

 to a point midway between the two dorsal fins, the 

 middle ones, one on each side, follow the lateral line 

 for some distance, and the lowest extends along the 

 belly to a point somewhat behind the ventral fins. 

 Of the sinuses, wliich are directed forwards, the upper 

 extends to the end of the first dorsal fin or even as 

 far as its .")th or 4th ray, and the lower to a, perpen- 

 dicular through the insei'tions of the pectoral and vent- 

 ral fins. Behind the corslet the lateral line is undu- 

 lating. The caudal carinsp are weaker than in the true 

 Tunnies. The pectoral fins are fairly short, being a 

 litth' longer than the ventral and somewhat less than 



V„ of the length of the body. They do not extend 

 quite so far back as tiu! first dorsal. The first two 

 rays in the first dorsal are the longest, the last two 

 very siiort and the last of all generally so short that 

 it scarcely ])ro)ects abo\e tiie margin of the fin-groove. 

 The second dorsal and the anal fins are low and scaly. 



The internal organs essentially correspond, accord- 

 ing to CuviER, to those of the Tunnies. The long- 

 tubular gall-bladder is especially remarkable. There 

 is no air-bladder. 



The colouring of the body, \vliicli on the whole 

 resembles that of the Tunnina (Euthi/nnits (dliUcniliis) 

 is particularly subject to variations in the distinctness 

 of the spots and of the dark, irregular, wavy transverse 

 streaks on the back, which sometimes seem to have 

 vanished entirely. The pectoral fins silver-gra\- on the 

 outside and black on the inside. The other fins gray, 

 the anal shading into yellow. 



The Frigate-Mackerel is common in .lapan, was 

 seen in crowded shoals by ('ommerson oft" New Guinea 

 and has long been known as a common fish in tlie 

 Mediterranean. Like the Pelamis, it has latterly ap- 

 peared in huge masses of the east coast of North Ame- 

 rica, where it has, however, been regarded up to now 

 as an unwelcome iiitruder, its flesh being less esteemed 

 than that of the other members of the family as it 

 rapidly turns lilack on exposure to the air. "Its oil 

 does not seem to be very abundant, and it \\\\\ hardly 

 pay at present to capture it solely for the purpose of 

 using its flesh in the manufacture of fertilizers," says 

 Bkown'-Goode. It is equally despised, according to 

 Risso, in the Mediterranean. When salted, hoAvever, 

 it is said to be eatable. According to Risso its weight 

 seldom exceeds 3 kgrm. Its greatest length is appa- 

 rently about 45 cm. The spawning-season is supposed 

 to be in August, when the female deposits her eggs, 

 which are whitish and enveloped in a reddish mucus. 



The Frigate-Mackerel has been met ^\■ith once or 

 twice off the Fnglish coast and on one, single occasion 

 in Scandinavian waters, at the fishing-village of Arild 

 (Scania), Avhere Baron Gvllenstjerna obtained a spe- 

 cimen .377 mm. in length, which Avas described by 

 Nii.ssoN and is now preserved in the Zoological Mu- 

 seum of Lund University. 



