136 U.S. NATIONAL MUSEUM BULLETIN 2 02 Vol. 3 



it; opercular opening pale internally; area around anal opening black 

 with white to gray iiTegular lines and blotches ; dermal spines of back 

 and sides whitish. 



Lateral line system a distinct white, thin line observable on head 

 circling eye, one branch across snout midway between eye and tip of 

 snout, another branch down vertically across cheek starting midway 

 between eye and opercular opening; the main branch of the lateral 

 line rising above opercular opening on top of head or occiput, then 

 sloping evenly and gradually downward to a point on caudal peduncle 

 just above posterior edge of base of anal fin from which it angles 

 posteriorly toward base of caudal fin. 



Ecology. — This species occurred in the lagoon and on the ocean 

 side of the reefs in deep surge channels where wave action was severe. 

 The largest specimen was taken on hook and line in Bikini lagoon. 



Suborder Diodontina 



Family DIODONTIDAE 



By Loeen p. Woods 



Genus DIODON Linnaeus 



Diodon Linnaeus, Systema naturae, ed. 10, vol. 1, p. 334, 1758 (type species, 

 Diodon hystrix Linnaeus). 



DIODON HYSTRIX Linnaeus 



Plate 144, C 



Diodon hystrix Linnaeus, Systema naturae, ed. 10, p. 335, 1758 (type locality, 

 India) . 



SPECIMENS STUDIED 



Bikini Atoll: 5 stations, 5 specimens, 260 to 380 mm. in standard length. 

 Guam: 1 lot, 2 specimens, 324 and 345 mm. 



Description. — Dorsal fin rays ii,12 or 13; anal rays ii,12 or 13; 

 pectoral rays i,21 or 22; branched caudal rays 4+3; gill rakers rudi- 

 mentary, 6 on anterior side, first arch, short, fleshy, conical. 



Depth of body about 3.1 to 3.4; width of body 2.6 to 3.0; length of 

 head 2.6 to 2.75; all in standard length. Snout 2.4 to 2.5; eye 3.8 

 to 4.1; least depth of caudal peduncle 4.3 to 5.1; length of pectoral 

 fin 2.0 to 2.5; length of longest dorsal ray 2.0 to 2.3; length of longest 

 anal ray 1.9 to 2.2; length of middle caudal rays 1.6 to 1.8; postorbital 

 part of head 2.2 to 2.4; interorbital 1.4 to 1.6; all in length of head. 

 Angle of snout profile about 48 to 50 degrees, slightly concave. 



Interorbital slightly concave, spines of forehead commencing about 

 even with level of middle of eyes above nostrils; spines of forehead 

 shortest, those above and behind pectoral longest; nostrils a short 



