124 



SUB-CLASS C HONDROPTERYGII. CARTILAGINOUS FISHES. 



fins producing some resemblance to the Weevil. Bloch has fancied it forms 

 a connecting link between fishes and insects, as he thinks the Flying Fish 

 connects them with birds. The jaws are beset with small teeth ; the eyes 

 prominent, pupil black, surrounded with a yellow ring ; the upper part of 

 the body is studded with variously-disposed protuberances, and in the middle 

 of the under part is a prominent, longitudinal ridge, from which the ven- 

 tral fins arise ; these consist each of a long, single ray, and above each pec- 

 toral fin is a similar ray, perhaps serving rather the purpose of angling for 

 the fry of other fishes than as organs of swimming, as Bloch observes ; the 

 tail is quadrangular ; the general colour is bluish, and that of the protuber- 

 ances brown ; the pectoral fins are broad, and thus having a resemblance 

 to wings, whilst the scaly covering of the body resembles the Sea Horse, 

 they have been named after Perseus's famous winged horse Pegasus. 



Other genera of this family : 



HIPPOCAMPUS Sea Horse. These curious animals have derived their 

 title from their filaments resembling the hairs of a caterpillar, and the pecu- 

 liar curve which the neck and body assume in drying like the head and 

 neck of a horse. 



SOLENOSTOMUS Tubular-mouth. The large ventral fins uniting with each 

 other and to the body like an apron behind the pectoral fins distinguishes 

 this from the genus Syngnathus ; this apron serves the same purpose as 

 the pouch of that genus, viz. to support the spawn. 



ORDER VI. PLECTOGNATHI. FIXED JAWS. 



Family GYMNODONTA; Naked Teeth. 



THE Gymnodonta have, instead of teeth, their jaws covered with a sub- 

 stance like ivory, laminated internally, and resembling the beak of a parrot. 



Diodon ----- Hystrix .... Round Diodon. 

 Orthragoriscus - - Oblongus - ... Oblong Sun-fish. 



Family SCLERODERMATA ; Hard Skins. 



Balistes .... CaprUcus - - - Mediterranean File-fish. 

 Ostracion - ... Triquetrum - - - Trunk-fish. 



CHARACTERS OF THE GENERA. 



1. DIODON (Gr. Sic, twice, and dSot/c, a tooth). Jaws projecting, and 

 together resembling the beak of a Parroquet ; the skin covered with large 

 sharp spines, moveable, numerous, and scattered over the whole surface of 

 the body. 



2. ORTHRAGORISCUS (Gr. dpOpayopiWoc, sucking pig). Gills furnished 

 with membrane and opercule ; jaws undivided, bare, and toothless ; body 

 compressed, truncated behind, and not capable of inflation ; tail very short 

 and verticle ; no ventral fins ; dorsal and anal deep pointed and connected 

 with the caudal fin, which is in form of a narrow band. 



1. BALISTES (Italian balestra, a crossbow). Eight teeth in each jaw ; 

 body compressed ; skin scaly or granular ; first dorsal fin spined ; second 

 soft and opposite the anal ; no true ventral fins, but the pelvis attached to 

 the bones of the shoulder, and sometimes having projecting processes. 



2. OSTRACION (Gr. oarpaKov, a shelT). Body polygonal, and covered 

 along the head with regular bony plates, forming an inflexible coat of mail, 

 so that no part is moveable except the tail, the fins, the mouth, and a kind 

 of lip which is situated about the branchial aperture, all of which pass 

 through holes in this armour ; jaws each furnished with ten or twelve coni- 

 cal teeth ; to the gills there seems merely a cleft edge with a cuticular lobe, 

 but within there are an opercule and six rays ; no ventral fins ; dorsal and 

 anal single and very small. 



GYMNODONTA, SCLERODERMATA. DESCRIPTION OF THE SPECIES. 



DIODON. These fish, of which Lacepede enumerates five species, are 

 natives of the seas of hot climates, living upon the Crustacea and sea-weed. 

 Like the other fish of the same family, they have the power of inflating 

 the belly, which then gives them the appearance of a chestnut in its bristly 

 shell, hence the French call them Orbes Epineux. 



One species, the Round Diodon (D. Hystrix), is figured on Plate 10. 



ORTHRAGORISCUS. This genus consists of the species JJiyiii/, 

 Short, and Oblong Sun-fish; the last of which is represented on Plate 10. 



The Oblong Sun-fish (O. Oblongus) is about two feet and a half ! 

 body twice as long as its breadth, and marked with small hexagonal figures. 

 Found in the Atlantic. 



Other genera of this family : 



TRIODON Three-toothed. It holds an intermediate place between 

 Diodon and Tetraodon, and by the long pelvic bone which sustains the 

 enormous dewlap, or fan-like disc of skin, it is connected with some of the 

 Bdistes. 



TKTRAODON Four-toothed or Globe-fish. The fishes of this genus m. 

 able to inflate the body like a balloon, by swallowing large quantities "t 

 air, which is received into a kind of 

 extensible crop, occupying the whole 

 length of the belly. When thus dis- 

 tended they turn belly upwards, float- 

 ing upon the surface of the sea, with- 

 out the power of directing their course ; 

 but they are not defenceless, as their 



inflation erects the spines upon their skin. When caught they make a 

 sort of noise, probably by the escape of the air from their bodv. Their flesh 

 is considered to be poisonous. 



BALISTES the Mediterranean File-fish (B. Capriscus) is the only one of 

 this genus found in Europe, the others are all natives of the Indian and 

 American seas. The Bdistes are remarkable for the first dorsal fin, which 

 is composed -of two or more spines connected together on a single hone 

 attached to the skull. The generic title is derived from the trivial name 

 of the B. Capriscus, Pesce Balestra, so called by the Italians, from its sup- 

 posed resemblance to the trigger of a crossbow, for, says Salviau, it 1ms 

 three spines capable of voluntary erection and depression, and although you 

 press the foremost and greatest never so hard, it will not stir, but if you 

 depress the last and least of all never so softly, the other two immediately 

 fall down with it. Artedi applied the name Bdistes to this genus, from a 

 supposed resemblance of the spine of the B. Monoceros to the ancient 

 battering-ram. The English name, File-fish, was given to it by Dr. Grew, 

 in his " Museum Regalis Societatis," " from the likeness which the foremost 

 bone upon his back hath to a file." They are remarkable for the brilliancy 

 of their colours ; and their flesh, seldom much esteemed, is considered 

 poisonous at particular seasons. 



OSTRACION Trunk-fish. The remarkable covering of this genus bears 

 some analogy to the dorsal and ventral shields of the Tortoises, or rather 

 to the bony armour of the Armadillos, their hard covering being indeed 

 bony, and the several portions of which it consists being so well joined to- 

 gether, that the whole seems but a single bone, in shape of an oblong box 

 or coffer. These fish are found only in Tropical Seas, and in the Red and 

 Indian Seas, and in that which bathes the American coast. They feed on 

 Crustacea and Testacea, the shells of which they easily break down with 

 their teeth. 



The species figured on Plate 10 is flie 0. Triquetrum, its body is trian- 

 gular, and without spines. 



SUB-CLASS. CHONDROPTERYGII. CARTILAGINOUS FISUES. 



THE skeleton of the cartilaginous Fishes has no bony fibres, but the cal- 

 careous matter is disposed in grains. The sutures of tlie cranium are in- 

 distinct, and the maxillary and intermaxilliary bones are reduced to mer- 

 rudiments, their place being supplied by the palatine or vomer. Chon- 

 dropterygii comes from the Greek -^ovlpot, a cartilage, and VTC pv-yiov, a fin. 



ORDER. ELEUTHEROBRANCHIATA VEL BRANCHIS 



L1BERIS. LOOSE GILLS. 



THE gills are fiee, having a single wide opening and a gill-lid ; but without 

 gill-rays. 



