62 



BULLETIN OF THE BUREAU OF FISHERIES. 



Dorsal xi-17; ana! iS; pectoral 20. Pores in lateral line 42 to base of caudal, 2 or 3 additional 

 pores beyond this point. 



Body about as deep as wide at the shoulders; interorbital space very broad, shallowly and evenly 

 concave, ctirved equally and continuously with the portion of the occiput within the occipital ridges; 

 a small blunt tubercle on posterior border of supraorbital ridge, a sharp constriction behind it; occipital 

 ridges well marked, more or less broken, converging backward to the little marked occipital tubercles; 

 nasal spines large and pungent, both nostrils in short tubes, the anterior the longest. No filaments 

 or papillae on head. 



Maxillary reaching a vertical slightly behind middle of eye; teeth cardiform, anteriorly in broad 

 bands in both jaws, posteriorly narrowed; the teeth are directed obliquely backward and are depressible 

 in that direction; the lateral teeth in the mandible a little enlarged. 



Preopercular spine slender, the tip e.xtending nearly to opercular margin, slightly forked; two 

 strong curved cusps above, the anterior much the larger; the 3 lower preopercular spines short, nearly 

 equal in length, the upper one slightly curved, directed downward, the middle one vertically down- 

 ward, the lower downward and forward; humeral spine short. 



Rough plates cover the nape as far back as the dorsal fin and extend forward over interorbital 

 space and to base of nasal spines; a line of plates extends vertically downward along posterior orbital 



Fig. 13. — Gymnocanthus detrisus, new species. Type. 



border to suborbital stay, and another along preopercular margin nearly to base of upper spine; the 

 opercular rib is largely plated; a few scattered rough plates behind pectoral, extending along sides 

 two-thirds distance to tip of fin. 



Dorsals separate ; fourth spine longest ; pectoral reaching third anal ray ; ventrals not reaching vent; 

 caudal convex, tnracate when widely spread. 



Color brownish above, with very fine vermiculating lines of olive; lower parts white, with more 

 or less silvery luster; very faint crossbars on back, one at origin and one at middle of spinous dorsal, 

 one between dorsals, two under base of soft dorsal, and one on caudal peduncle; these bars are formed 

 by the dixrker markings becoming coarser and more intense, but the lighter vermiculating lines are 

 present; front of upper lip colored like top of head; a dark bar across maxillary near its middle; a 

 dusky bar across lower lip on each side symphysis; a broad dark brown margin on spinous dorsal and 

 an irregular dark bar on middle of fin parallel with the margin; 5 bars of reddish brown on soft dorsal 

 running downward and backward; 3 reddish brown bars on the caudal, running a little obliquely 

 downward and backward; 2 broad bars on pectoral, with sometimes a faint third bar nearer base; 

 ventrals and anal plain. 



The species is most closely related to G. hcrzcnstcini Jordan and Starks, and differs in the much 

 wider interorbital, the larger eye, the smaller mouth, the longer preopercular spine, the coloration, 

 and in numerous other details. 



