HISTORY OF THE FISHES OF MASSACHUSETTS. 223 



PLECTOGNATHI. 



The maxillary bone soldered or fixedly attached on the side of the intermaxillary, 

 which alone forms the jaw, and to which the palatine arch is dovetailed by a 

 suture within the cranium, and consequently has no power of motion. Opercula and 

 the rays concealed under a thick skin, which only permits a small branchial cleft 

 to be visible externally. 



• FAMILY XXIV. GYMNODONTID^F. 



Instead of apparent teeth, the jaws are furnished with an ivory substance, divided 

 internally into laminae, the general appearance of which somewhat resembles the bill 

 of a parrot, and which is essentially composed of true teeth united together, and 

 succeeding one another in proportion as there are any worn out by trituration. Oper- 

 cula small ; their rays five in number. 



GENUS I. TETRODON, Linn. 



Jaws divided in the middle by a suture, presenting the appearance of four teeth in 

 front, two above and two below. The skin over a portion of its whole extent covered 

 with prickles. 



Tetrodon turgidus, Mitchill. 



The Swell-fish. Puffer. 

 (Plate XXXIII. Fig. 5. b. Jaws.) 



Tetraodon turgidus, Puffer, Mitch., Trans. Lit. and Phil. Soc. of N. Y., I. p. 473, pi. 6, fig. 5. 

 " " Swell-Jish, Puffer, Stoker, Report, p. 169. 



" " Common Puffer, Dekay, Report, p. 327, pi. 55, fig. 178. 



" " " Ayeks, Bost. Soc. Nat. Hist., iv. p. 285. 



" " " Stoker, Mem. Amer. Acad., New Series, n. p. 493. 



" " " " Synopsis, p. 241. 



Color. Upper part of the body ash-colored, interspersed with light pea-green, with 

 large irregular patches of greenish-brown. Sides orange, with a shade of brown, 

 barred transversely by seven or eight blackish irregularly defined bands. Abdomen 

 yellowish-white. Head' greenish-brown. Pupils green, hides orange. Fins color of 

 abdomen. 



Description. Body oblong, cylindrical, globular when inflated. The whole surface 



