358 



U.S. NATIONAL MUSEUM BULLETIN 202 



Vol. 2 



traces of spots basally. Background coloration of females light tan, 

 with numerous small brownish spots on head and body separated by 

 whitish interconnecting lines or streaks; lower sides with double or 

 A-shaped bars; dorsal and caudal fins barred with small black spots; 

 anal fin with dark pigment distally but tips of rays whitish and the 

 membrane between every other anal ray dark brownish; lower lip 

 usually edged with dark brown; under side of head with 3 transverse 

 brownish bars, rear bar usually interrupted near midventral region 

 and front bars more or less joined midventrally by diffuse brownish 

 pigment. 



Color when alive. — The whitish lines or narrow spaces between the 

 light brownish spots probably were reddish and in alcohol fade out 

 to whitish. 



Ecology. — This species was taken on the open reef and in channels 

 where wave action was strong. 



Remarks. — This species is closely related to /. gibbifrons and /. roden- 

 baughi, new species, differing in certain details of color pattern as 

 described and compared in the key, especially in regard to the brown 

 transverse bars, not occurring on the other two species, which are 

 found on females on under side of head. 



Named aj'ilinuchalis in reference to the absence of the nuchal 

 filament which often occurs in other species of the genus Istiblennius. 



Table 114. — Certain measurements on holotype and a paratype of Istiblennius 

 rodenbaughi and I. afilinuchalis, expressed in thousandths of the standard length 



Characters 



7. rodenbaughi, new 

 species 



Holotype Paratype 



/. afilinuchalis, new 

 species 



Holotype Paratype 



Standard length in mm. (frontmost part of head to base 



of caudal fin) - 



Head 



Greatest depth of body 



Least depth of body -- 



PostorbitaJ length of head 



Eye 



Snout — — 



Interorbital space (fleshy) 



Length of orbital cirrus 



Longest dorsal spine 



Longest soft dorsal ray 



Longest soft anal ray 



Longest pectoral ray 



Longest pelvic ray --- --- 



Longest caudal ray.. - 



Snout tip to anus 



Snout tip to dorsal origin 



Length of anal fin base 



79 



222 



165 



92 



166 



49 



67 



18 



42 



120 



152 



146 



186 



133 



228 



494 



177 



430 



75.6 

 226 

 199 

 105 

 144 



52 



72 



15 



28 

 117 

 142 

 103 

 183 

 138 

 208 

 496 

 191 



73 



214 



168 



100 



149 



65 



79 



14 



42 



116 



164 



145 



157 



130 



205 



452 



185 



437 



69.5 

 227 

 175 



84 

 158 



54 



77 



17 



42 

 124 

 138 

 123 

 202 

 143 

 223 

 474 

 217 

 424 



ISTIBLENNIUS RODENBAUGHI. new species 



Plate 117,F 

 Holotype.— USNM 142067, Bikini Atoll, Namu Island, ocean reef 

 and surf, August 7, 1947, S-1019, Brock, Hiatt and Schultz, standard 

 length 79 mm. 



