No.l2^. GYMXODONT FISHES OF JAPAN— JORDAN AND SNYDER. 255 
23. EUMYCTERIAS RIVULATUS (Schlegel). 
KITAMAKURA (SLEEPER WITH IIPIYD TO NORTH); YOKOBUKU 
(CROSSWISE PUFFER); AKAMEBUKU (RED-EYED PUFFER). 
Teirodon rivulatus Schlegel, Fauna Japonica, Poises., 1847, p. 285, pi. cxxiv, 
fig. 3, Nagasaki. — Gdnther, Cat. Fish., VIII, 1870, p. 305 (copied). — Ishi- 
KAWA, Prel. Cat., 1897, p. 2, Sagami, Tokyo. 
Tetrodon grammatocephalus Schlegel, Fauna Japonica, Pois8., 1847, p. 286, pi. 
cxxvi, fig. 3, Nagasaki (young with obscure coloration). 
f Eumycterias hitxniatus Jexkixs, Bull. U. S. Fish Comm., 1899 (June 8,1901), 
p. 400. Honolulu. 
Head 2f in length; depth 2|; depth of caudal peduncle 2^ in head; 
e,ye 4i; snout If; interorbital space 3f ; dorsal rays 10; anal rays 10. 
Bod}^ robust, deep, compressed, the dorsal contour greatly elevated, 
the outline from snout to occiput straight, the ventral contour evenly 
rounded; caudal peduncle deep, compressed, its length 1| in head. Head 
triangular in outline, its length equal to distance between gill-opening 
and dorsal fin; interorbital area narrow, nearly flat. Eye oblong, 2^ 
in snout. Snout long, pointed. Nostrils with a single tube in a small, 
round papilla. Teeth scarcely pointed anteriorly, the cutting edges 
straight, the suture without a deep groove; no vertical ridge on 
either side of groove. Width of gill-opening equal to one-half base 
of pectoral. 
A median elevation or fold of the skin extending from chin to anal 
opening. Skin smooth or with embedded prickles on adult specimens 
(100 to 150 mm. long). Young individuals with prickles above and 
below. With increasing age the prickles sink into the thick skin and 
entirely disappear. In dried specimens the}^ are present, having 3 
roots. 
Color, olivaceous above, bright violet below. Adults marked above 
with numerous narrow l)right blue lines running in various directions 
on the nape and back, mostly longitudinal on front of snout, and on 
back of tail, and descending vertically or obliquely about the eye; 
besides these lines are numerous vermiculations, especially on bod}^ 
and tail, while the belly and sides are sprinkled with orange dots. 
These are especially numerous above and behind the chin and about 
the gill opening. Belly with blue spots. All these markings are 
variable and some of them fade in spirits. Dorsal blackish at base, 
otherwise pale; caudal dusky bluish, its base dusky above and below. 
Specimens of about 150 mm. are marked as above. Those of about 
100 mm. have in addition a dark curved line before gill opening, the 
upper part of which extends backward toward caudal. Smaller ones 
show in addition two blackish lateral stripes, the one extending from 
the eye nearl}- to the caudal, the other from the tip of snout, below 
pectoral; dark streaks before and behind gill-opening. Still smaller 
ones lack streaks and spots and have two black lateral bands, with 
a silvery interspace. 
