398 BULLETIN 152, UNITED STATES NATIONAL MUSEUM 



Measurements. — Male holotype, length of carapace 4.9, width 6.6^ 

 fronto-orbital width 4.5, width of front 2.6 mm. 



Range. — West coast of Mexico. Known only from the type 

 specimen, 



HEXAPANOPEUS SINALOENSIS, new species 



Plate 170, Figures 1 and 2 



Type-locality. — Teacapan, Sinaloa, Mexico; on oyster beds especi- 

 ally among bunches of Hydrozoa; Secretaria de Agricultm"a y Fo- 

 mento; 1 male holotype (Cat. No. 60229, U.S.N.M.). 



Diagnosis. — Carapace deeply furrowed. Front arcuate, without 

 tooth at outer end-s. Supra-orbital lobe set off on either side by an 

 open fissure. Second antero-lateral tooth much larger than first; 

 third wider than fourth. 



Description. — Regions and subregions of the dorsal surface of the 

 carapace marked off by deep furrows; transverse granulated lines 

 inconspicuous. Front thin, not crossed by the median epigastric 

 groove; edge arcuate, scarcely interrupted by the minute notch at 

 the middle, and without a tooth at the outer ends. Inner supra- 

 orbital tooth large, outer edge longitudinal, inner oblique; space 

 between fissures broad, transverse, fissures open, terminating in a 

 V-notch; inner suborbital tooth low, reaching only as far as the line 

 of the base of the supra-orbital tooth. Outer tooth small, only a 

 third as wide as the second tooth of lateral margin and separated 

 from it by a narrow sinus; second tooth shallow, inner margin nearly 

 transverse, outer margin sinuous, directed backward and outward; 

 third tooth broadest, a lobule on its inner margin, outer margin 

 nearly longitudinal; fourth tooth narrow-triangular, a minute lobule- 

 at base of inner margin, outer margin oblique and slightly convex; 

 fifth tooth very small but well formed, directed obliquely forward. 



The chelipeds, which are detached and very unequal, are rough,, 

 the carpus lumpy toward the distal end, the manus very rough above 

 and with a deep superior furrow. Both chelipeds have the fingers 

 strongly deflexed and the dactyl without a large basal tooth. They 

 have the appearance of minor chelipeds and may not both belong to 

 the type-specimen. The color of the fixed finger runs back a little 

 on the palm in a horizontal line, then turns obliquely downward,! 

 forming a line parallel to the proximal margin of the palm. 



Abdomen (male) rather narrow, the third segment not reaching: 

 the coxae of the last pair of legs; sixth segment broader than long, 

 its sides sinuous; terminal segment slightly broader than long, sub- 

 triangular. 



Measurements. — Male holotype, length of carapace 6.2, width 8.5,. 

 fronto-orbital width 5.7, width of front 3.2 mm. 



Range. — West coast of Mexico. Known only from the type 

 specimen. 



