328 JPlsui'^S. 



The genera Tetraodon ana Viodon liave the faculty of blowing themselves up like balloons, by filling 

 with air a thin and extensile inemljranous sac, which adheres to the peritoneum the whole length of 

 the abdomen. "When tliiis inflated, they roll over and float with tlic IjcUy uppermost, without any 

 power of directing their course ; but they are remarkal>ly well defended by spines all over the surface, 

 which are erected as they are inflated. Their air-biadder has two loljes. They have but three gill- 

 arches in a iside ; and when taken, the escape of the air from the pouch makes a sound. Each nostril 

 is furnished with a double fleshy tentacidnra. 



Diodon, Spinous Globe-tislies, ^et the generic name from tlie Jaws consistin^i; of only two piecps, one above and 

 tlie other below. Behimi the trenchant edge of each piece, there is a rounded portion furrouefl across, imd 

 forminij a powerful grinding- apparatus. The spines upon the inflated skin, which vary a ^■■ood deal in the dif- 

 ferent species, present a formidable appearance. They inhabit the warm seas ; but sometimes, tlioui,^li rarely, a 

 specimen, brou;2;ht no doubt by the Atlantic current, is found on tbe coast of Cornwall. 



Tetraodon, have each jaw marked with a suture, so as to tfive the appearance of four teeth. The spines are 

 small and low, and some species are reckoned poisonous. None of them is recorded as visiting; Britain. One is 

 electrical, T. Uneatns, strai};'ht, brown and \\hitish: it is found in the Nile, cast on shore by tbe inundations, and 

 collected by the children as a jtlaythini;. 



Orthagoriscus, the Sun-lisli, has the body compressed, spineless, and incapable of inflation, with the tail so short 

 that it appears only the anterior half of a Jish which had been cut in two in the middle. Their dorsal and anal, 

 both high and pointed, are united to the caudal ; no air-bladder, and the stomach is small ; their surface is covered 

 with mucus. They are found in many seas; and two species at Icast^O. mola, the l^'hort £un-iit.h, and O. oOlo/zgus, 

 the Oblong Sun-tish— are found in the British seas. 



Triodon. — These species have the mark of a suture on the upper jaw, but none on the under, which gives them 

 the api)earance of having three teeth. A vast membrane, as long as the body, and twice as high, is supported 

 before by a large bone answering to the pelvis, and makes these fishes reseml)le Batistes, in the following family. 

 Fins as in Diodon, body rough like Tetraodon, and the surface of the membrane roughened by a number of little 

 oblique crests. The only known species is from the Indian Ocean. 



THE SECOND FAMILY OF THE rLECTOGNATHI. 



ScLERODERMi (Fislics with Hard or Granulated Skins). 

 These arc readily distinguished l>y a conical or pyramidical muzzle, ^\hicli is prolonged forwards from 

 the eyes, and terminates in the mouth, with distinct teeth in both jaws. The skin is either rough or 

 covered with very hard scales; and the air-bladder is large, strong, and of an oval shape. There are 

 two griicra. Batistes, File-fishes, admit of subdivision, and have the body compressed; eight teeth, 

 gener;dly trenchant, in a single row in each jaw ; the skins hcaly or granulated, but not osseous ; the 

 first dorsal composed of one or more spines, articulated with a particular bone, which is attached to 

 the craiaum, where is a groove for its reception ; the second dorsal and anal long, and placed opposite 

 each other. Though without ventral fins, they have pelvic bones attached to the shoulders. They 

 abound in the warm seas near rocks, or on the surface of the water ; and their brilHant colours sjiarkle 

 in the water like those of Chetodons. Their llcsh is disliked at all times; and they are supposed to 

 feed on Curalline Pulypi at some seasons, and become poisonous, but Cuvicr found only sea-weed in 

 such as he opened. 

 Bali'ites proper, ha^e the \^hole hudy covered uith long and bard rhomboidal scales, which do not overlap each 



other, Init have the appearance of the teeth of a iile ; three 



J\:^ Spines (111 tbe dor^al, the first long, the IhiiHl small and far 



f:^, back; extremity of the ehest ^ulieid and prickly, with 



^'^ some spines in the skin behind, \\\ur\\ have been con- 



sidered as rays of ventral fins. Some have no particular 

 armature of the tail ; and of these, again, some have large 

 scales behind the gill-opeuiugs. Such is the liuropean 

 \ File-lish — B. capriscus, -which has been occasionally, but 



''f very rarely, found on the British shores, and which is com- 



■>~, mon in the Mediterranean. 



Monacanflius. — This subgenus has very small scales, set 



^ »^ rungli like the pile of velvet ; a large cirrated spine on the 



y '1 first dorsal, and the extremity of the pelvis salient and 



— ^i A Spinous. Some have the pelvic bone moveable, and ctin- 



1 nected with the abdomen by an extensile membrane, and 



'^/\/ ^ frequently strong spines on tbe sides of the tail. Some have 



stout bristles on the tail, some have the budv wjth tubcr- 



les pciiLiliii^'enis, ' 



clcs, and others with branched hairs. 



