126 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.43. 



dorsal space 2.60 in head; second dorsal rays small, especially the 

 anterior ones; anal well developed, its rays long and slender; ventrals 

 small, inner rays reaching origin of anal, outer ray filamentous 1.93 

 in head; pectorals 1.93. 



Color in alcohol: Ground color dark sepia brown, under side of 

 throat posteriorly, belly and fins blackish; inside of mouth blackish. 



TijjM.— Cat. No. 72942, U.S.N.M., 27 cm. in length, taken with a 

 beam trawl at station 5492 (lat. 9° 12' 45" N.;long. 125° 20' 00" E.), 

 between Leyte and Mindanao, at a depth of 735 fathoms, on a bottom 

 of gray mud. 



M. adpenserinus (Gilbert and Cramer) and M. microstomus (Regan) 

 are closely related species and all 3 may prove inseparable. In 

 adpenserinus the snout, particularly the part in front of angulation, 

 is longer and more pointed, the bifid tip more prominent, the number 

 of pectoral rays appears to be somewhat greater, and the coloration 

 is much lighter. The description of microstomus is too scant to admit 

 of satisfactory comparison; in it the eye is larger, the interorbital 

 relatively narrower, and in the figure the outer ventral ray is not 

 filamentous. 



MAT^ffiOCEPHALUS ADUSTUS Smith and Radcliffe, new species. 

 Plate 28, fig. 3. 



Dorsal ii,9-85+ ; anal 100+ ; ventrals 7; pectorals 16. 



Head 4.80 in total length, depressed, dorsal contour nearly straight, 

 oblique, no traces of occipital ridges; suborbital ridge sharp, ending 

 as in other species of the genus near vertical from posterior margin 

 of eye; body slender, compressed, greatest depth 7.40 in total length; 

 vent immediately in front of anal; tail slender, compressed; eye 

 small, subelliptical, horizontal diameter 3.88 in head; interorbital 

 4.33, narrow, flat; snout 2.90, broad, depressed, bifid tubercle at tip 

 less prominent than in related species, projection of tip beyond angu- 

 lation relatively short, groove less distinct, more completely scaled, 

 rendering this portion of snout less mobile than in nigrescens; mouth 

 small, its distance from tip of snout 3.34 in head; mandibular barbel 

 short, slender, hair-like; teeth slender, in narrow cardiform bands; 

 scales small, regular, 7 in each series from origin of dorsal and from 

 last dorsal ray to and including lateral line, spinules on exposed por- 

 tion of scale very slender, arranged in about 18 nearly parallel rows 

 (the number somewhat less in the young), those on head small, hair- 

 hke; under side of head scaled. 



First dorsal spine slender, longer than in most related forms, second 

 spine long, slender, longer than head, 4.52 in total length, basal por- 

 tion armed with several weak, very widely separated s]3inules; inter- 

 dorsal space 2.37 in head; second dorsal low, its rays very slender; 

 anal rays better developed than those of second dorsal; ventrals 



