ACANTHOPTERYGII 299 
fishes, for the rapidity with which it dies when out of the water, and also becomes putrid, or tainted. 
I There are several species in the European and American seas. 
i Thynnus, the Tunny, has a soft corselet of large scales on the thorax, a cartilaginous keel between the crests 
and the sides of the tail, and the first dorsal approaching the second. It is very abundant in the Mediterranean, 
I where it sometimes attains the length of fifteen or eighteen feet. It is captured in vast numbers, and forms an 
; essential article of the food of the people. It has been known in the Mediterranean from the remotest antiquity, 
I and occasionally appears on the Bx'itish coast. There are several species, of which the Bonito, or Striped Tunny, 
is one of the most striking. 
; Orcynus, has the pectoral fins much longer than the Tunny, the back blackish, the belly silvery, and the flesh 
^ much whiter than that of the Tunny. In summer, it visits the Mediterranean and Bay of Biscay, in shoals. [Most 
j of the Scomberidse frequent the shores in summer, for the purpose of depositing their spawn ; and they subsist, in 
' great part, upon the fry of the later spawners, as these again live upon theirs, which is a beautiful adaptation, 
whereby the immense surplus of one family of fish adequately supplies the wants of another.] 
' Auxis, have the corslet and short pectorals of the Tunny, and the separate dorsals of the Mackerel. Found in 
the Mediterranean. Of a fine blue on the back, with oblique blackish lines, and the flesh deep red. A West Indian 
I; species equals the Tunny in size. 
Sarda, differ from the Tunnies in having the teeth separate, strong, and pointed. The only known species in- 
habits both oceans, and is common in the Black Sea and Mediterranean, 
j Cybium, have the body long, no corselet, jaw-teeth large and lancet-shaped, parietal teeth small, short, and 
’ crowded. Found in the warm parts of both oceans ; and some of the species grow very large. Thyrsites, has the 
jl front teeth longer than the others, pointed teeth on the palate, and no lateral keels to the tail. 
Gempylus, have jaw-teeth similar to the last, but no parietal teeth, and the ventral fins scarcely perceptible. 
I [These are the subgenera of Scomber, and the remaining Scomberidae have characters somewhat different.] 
I Xiphias, the Sword-fishes, resemble the Tunnies in their very minute scales, the keels in their tails, 
i! the power of their caudal fin, and their whole internal organization. Their distinguishing characteristic 
is a long pointed beak, formed like a sword or 
spit, which terminates their upper jaw, and is 
a most powerful offensive weapon, with which 
they attack the largest animals in the ocean, 
[and sometimes drive it into the timbers of 
ships, where it breaks, and a portion is left]. 
This beak is principally composed of the vomer 
and the intermaxillaries, and supported at its 
base by the ethmoid and the frontal maxil- 
laries. Their gills are not divided like the teeth of a comb, but each consists of two large and parallel 
laminae, with reticulated surfaces. They swim with extreme rapidity, [and it is probable that the 
I peculiar gills enable them to do this with safety, not being liable to get entangled like those in threads]. 
J Their flesh is excellent. The subgenera are, — 
j Xiphias, the Sword-fish, properly so called ; has the beak long, flattened horizontally, and trenchant, like the 
I blade of a large sword ; sides of the tail with strong keels ; only one dorsal, which wears in the middle in old speci- 
j mens, and then seems two. This is one of the largest and best fishes in the European seas, and is frequently fifteen 
' feet long. It is very abundant in the Mediterranean, but less so in the Atlantic. Notwithstanding its formidable 
weapon, its great strength, and its almost incredible celerity, a small crustaceous animal penetrates the flesh of 
the Sword-fish, and sometimes so torments it that it dashes itself on the shore with mortal violence. 
Tetrapturus. Beak shaped like a stiletto; each ventral consists of one jointless blade; two small crests on 
I each side of the base of the caudal, as in the Mackerel. [These lateral crests on the tail appear to steady that 
i powerful organ, and thus render it more efficient and unerring in its intense labour.] One species inhabits the 
I Mediterranean. 
j Makaira, like the former, but wants the ventral plates ; rather a doubtful species. 
! Istiophorus, has the beak and caudal crests like Tetrapturus, but the dorsal high, and serving as a sail in 
I swimming ; and the long and slender ventrals are composed of two rays each. Several species have been named, 
I but they are imperfectly known. All the Sword- 
; fishes attain a large size, [and the dorsal fin is subject 
i to variations]. 
Centronotus, a genus having free spines in- 
; stead of the first part of the dorsal, and ventrals 
I in all the species. The subgenera are, — 
I Naucrates, the Pilot-fish, has spindle-shaped body, 
[ free dorsal spines, keel on the tail as in the Herring, 
and two free spines before the anal. The Common 
Fig- 135 .— The Pilot-fish 
