Plectognaths.- 
-FISHES.- 
-GyaiNODONTS. 
Turkey-fish (Tetraodon meleagris), 
and is united at the base to the caudal. No air-bladder 
is present, and the small stomach is entered directly by 
the bile-duct. The arterial stem is provided at its 
origin with four semilunar valves. The skin is smooth 
in some species, and in others is armed by scattered 
spines. The myelon is greatly abbreviated. The 
The genera are — Cibotion-, Doryophrys; 
Ostracion; Aracana; and Centawus . — (See 
Kaup, Cut. Brit. Mus.) 
Family III.— GYMNODONTS 
( GymnodontidcB) . 
Plate 13, figs. 67, 68. 
hired. It is an inhabitant also of the Mediterranean, 
Atlantic, and Indian Ocean. — Plate 13, fig. 65. 
Fig. 45. 
opening is only a short slit, bordered by a skinny edge, 
but interiorly it has an operculum and six branchio- 
stegals. The box-like mail is in 
some species rectangular ; in others 
triangular in section, or it is oval or 
orbicular. The liver is large and 
oily ; the stomach capacious and 
membranaceous. 
Gilded Trigger-fish (Xanthichthys curassavicus). 
The Balistids and Cofier-fishes, or Ostracionids, con- 
stitute the family of ScUrodh'mea of Cuvier. 
Family II. — OSTRACIONIDS {Ontracionidce). 
Plate 13, fig. 66. 
These Coffer-fishes have the body inclosed in a 
tesselated cuirass of scales arranged quincuncially, 
forming a box of little or no flexibility, from out of 
which the lips, teeth, pectorals, and tail with its three 
vertical fins protrude. The pelvic bones and ventrals 
are wanting. The vertebrse of the belly are mostly 
coalescent, and the body has but little muscular sub- 
stance, its motions being limited. Exteriorly the gill- 
This family, characterized by Cuvier 
under the name of Gymnodonts, com- 
pi'ises his Diodonts., Tetrodonts, Trio- 
donts, and Moles or Sun-fish. Its 
members have the teeth incorporated 
in the gorget-shaped jaws, forming a 
bill like that of a parrot. Cuvier’s 
genera have been described by Dr. 
Kaup as families or sub-families. 
The Diodonts have a flexible skin which, in most 
species, is inflatible so as to give a globular shape to 
the fish, and is armed with spines which diverge every 
way when the skin is distended. No mesial division 
exists in either the upper or under jaw, each having 
the form of a horse’s hoof, with the teeth incorporated 
in their bony substance. 
The genera axe—Diodon ; Dicotylichthys ; Cheilomycterus ; 
Cyclichthys ; and Cyanickthys ; none of which are British. 
The Molebuts or Sun-fishes {Orthagorisdni) 
have jaws like the Diodonts, and are compressed fishes 
incapable of inflation, and a tail so short and high as to 
seem as if docked off. The dorsal is high and pointed, 
Fig. 46. 
