280 



ICHTHYOLOGY. 



terous 

 Fishes. 



Classifica- TABLE OP GENERA. 



tion — ^o free rays in advance of the dorsaL 

 Acanthop- Two dorsals. 



A'paralletopiped head. 



Free rays beneath the pectoral. 



Trigla, Prionotus, Peristedion. 

 Long rays beneath the pectorals, united to form great fins 

 used as wings. 

 Dactylopterus. 

 No detached ray.s under the pectorals. 



CEPHAL.4CANTHUS. 

 A round or depressed head. 

 Ventrals under the pectorals. 



COTTUS, IlEMITRIPTERUS, BEMBRAS, ASPIDOPHORUS. 



Ventrals behind the pectorals. 

 Platycefhalus. 

 A single dorsal. 

 A compressed head. 



Villiform teeth on the jaws, vomer, and palatines. 



HEMILEPIDOTUS, BLEPSIAS, ApISTES, SCORP.ENA, Se- 

 BASTES. 



Teeth on the jaws and front of the vomer, but not on the 

 palatines. 

 Ptekoxs. 

 Some small teeth on the jaws only. 

 Agriopus. 

 A large head ; monstrotis in appearance ; eye on the dorsal 

 aspect, 

 Villiform teeth on the jaws and front of the vomer. 

 Pelor. 

 Free spines replacing the first dorsal. 



Body scales large and imbricated ; eight branchiostegals. 



MONOCENTRIS. 



Body mailed by plates on the lateral line ; three branchi- 

 ostegals. 

 Gasterosteus, Spinaciiia. 



Fig. 9G. 

 Trigla pleuracanthica. 



The TrigJcB or Gurnards are too well known to need a 

 description ; at tlie same time tliey convey a good idea ot" 

 the general form of'one of the lead- 

 ing tribes of tlie timiily, and one in 

 which the characteristic develop- 

 ment of the second suborbitar 

 scale bone is well seen. This bone 

 in all the Sclerogeiioids either 

 covers the whole cheek, or sends a 

 process across it to the curve ot 

 the preoperculum opposite to the 

 spine at the angle, to which it 

 serves as a point of resistance 

 when the spine is used as a wea- 

 pon. This elongation of the sub- 

 orbitar is often crested by an acute 

 ridge, and is most commonly armed 

 with spinous points. The air-blad- 

 ders of the Gurnards are variously 

 lobed, and some of the species have been noticed to emit 

 a grunting noise when caught, which some observers have 

 supposed was produced by that organ ; but it is the charac- 

 ter of the order to have no air-duct to the swim-bladder. 

 The flesh of the Gurnard is very white, firm, and wiiolesome. 

 The common Dactylopterus or Flying-fish of the Medi- 



terranean {Trigla volitans, Linn.), is a species too remark- Classifica. 

 able for its functions, so opposite to those of its class in gene- tion — 

 ral, not to have attracted from an early period the attention of Acanthop- 

 mankind. It is extremely common, and has been men- J!"^?"^ 



tioned by all the autliors who have treated of the fishes of ^ ' , 



that inland sea. The ardour with which it is pursued by "" ^~^ 

 the Dolpliins and Bonitos, the sudden effort v\ hich it makes 

 to escape these predaceous creatures by vaulting into the 

 air, the new and probably unthought of dangers w hich there 

 await it from gulls and otlier aquatic birds, render it an 

 object of the highest interest to the unaccustomed lands- 

 man, somewhat wearied with tlie monotony of a sailor's 

 life. " It is by the extension of the pectoral rays and mem- 

 brane that the fish is enabled to raise itself from its proper 

 element to tlie regions of the air, though this is by no means 

 a continual flight, for the utmost it can do is to describe an 

 arc over the surface of the water e.vtending to a distance 

 of about 120 feet, and sufficiently elevated for the fish some- 

 times to fall on the deck of a large vessel. This power of 

 flight or momentary suspension would be much greater if 

 the pectoral membrane could preserve its humidity longer, 

 but it is soon evaporated in the heat of the tropics; and the 

 membrane, as it becomes dry, loses its buoyant power, and 

 the fish fills. They are sometimes so numerous as to afford 

 much pleasure to the spectator by their repeated flights ; 

 and at particular times, especially on the approach of rough 

 weather, in the niglit, numbers of them may be seen, by 

 the phosphoric light they emit, marking their arched pas- 

 sages in apparent streams of fire." Such is the current 

 account of the flights of this interesting fish, and of the 

 causes of it ; but it is probable, as has already been ob- 

 served of the Exocati, that the Flying-fishes do not soar 

 into the air merely when pursued by their enemies, for this 

 would only be incidere in Sci/llam ciipiens vitare Cliaryb- 

 di)n, but also to subserve some purpose in their economy. 



The Cotti are characteristic members of anotlier group 

 of the Mailed Cheeks. The fresh-water species of this 

 genus have the head almost smooth, and only a single spine 

 to the preopercle. Their first dorsal is very low. The 

 most common is the river Bull-head {CottiM gohio, Linn.), 

 sometimes called the Miller's Thumb. It is a small dark- 

 coloured fish, 4 or 5 inches in length, and frequent in most 

 of the streams of Europe and the north of Asia. It usually 

 lies concealed beneath stones, from whence it darts with 

 great rapidity upon its prey. It is said to be extremely pro- 

 lific ; and the female, when with spawn, becomes so greatly 

 enlarged, that her ovaries protrude like mammae. The Bull- 

 head, like the Salmon, has a reddish hue when boiled. It 

 affortls a good and wholesome food, much sought after by 

 the mountain tribes of several countries. 



The ScorjiceiuB are found in all seas in considerable num- 

 bers, and present a great variety of aspects, some being 

 nearly as ugly as a Pelor, while others passing, as it w ere, 

 into the nearly allied genus Sebastes, liave a Percoid neat- 

 ness of appearance. The species here figured is an Aus- 

 tralian one, ScorjXBiia Stokesii. 



rig. 97. 



Trivia pleuracanthica 

 scale from the lateral line. 



Fig. 98. 

 Scorpcena Stokesii, 



The Platycephali may be considered as elongated and 



