256 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxiv. 
Some specimens of 100 mm. (Nagasaki), corresponding to grammato- 
cephalus, lack streaks except about the eye, have no spots, the belly 
plain whitish, and the dark lateral streaks vaguely defined, the body 
mottled or blotched with paler. 
Comparison of ver}^ many specimens from Tok}^©, Misaki, Waka- 
noura, Kobe, and from Nagasaki leaves no doubt that all belong to a 
single species which varies much with age, as well as with the sur- 
rounding conditions. Additional variations arise in alcohol, which 
causes the fading of the violet and golden markings. 
Southern Japan, common in shallow bays about rocks from Tokyo 
to Nagasaki. The description of Emnycterias hitmiiatiis from Hono- 
lulu applies ver}^ well to a young specimen of this species. 
{Hlvulatus, having streaks like streams.) 
Family IV. DIODONTID^. 
PORCUPINE FISHES. 
Body short, broad, depressed above. Bell}^ moderately inflatable; 
body covered ever^^where except on the lips and caudal peduncle with 
spines, which are usually 2-rooted or 3-rooted at their bony base. 
Caudal peduncle short and slender. Mouth moderate, terminal, each 
jaw covered with a bony plate like the beak of a bird; these not divided 
by a median suture. Nostrils on each side forming a small tentacle, 
usually with 2 openings. Eye rather large, gill opening moderate, 
immediately in front of the pectoral, which is short, broad, and 
rounded. Dorsal and anal fins short, similar to each other, rounded 
in form and placed posteriorl3^ Sluggish fishes, living on the bottom 
among weeds and corals, in tropical seas. When disturbed, they 
swallow air and float belly upward on the water. Their capacity of 
inflation is very much less than that of the Tetraodontidoe,^ from which 
family they" differ chiefl}' in the stronger armature and in having no 
division in the bony plate of either jaw. They are rarel}^ used as 
food, being generally regarded as poisonous. The species are mostly 
well known in collections, the singular form having attracted the 
attention of travelers in the earliest times. 
a. Dermal ossifications mostly 2-rooted; the spines rather slender, but stiff and 
erectile. Nasal tentacle simple, with 2 lateral openings Diodon, 5. 
aa. Dermal ossifications all or nearly all o-rooted, each with a short, stiff, immovable 
spine. Nasal tentacle simple, with 2 openings C}dlo)nycterus, 6. 
5. DIODON Linnaeus. 
Diodon Linnaeus, Syst. Nat., 10th ed., 1758, p. 335 {Jtystrix). 
Paradiodon Bleeker, Atlas Ichth., Gymnodontes, 1867, p. 56 {Itijstriv); name a 
substitute for Diodon, transferred to another genus; the first species mentioned 
by Linnteus being Diodon atinga, which was therefore taken by Bleeker as 
the type. 
Body robust, the bell}^ moderately inflatable. Dermal spines strong, 
stiff', most of them 2-rooted and erectile, a few 8-rooted and therefore 
