1710 Bulletin //, United States National Museum, 



2125. XANTHICHTHYS MENTO (Jordan & Gilbert). 



Head 3|; depth 2f. D. II-I, 29; A. I, 26; scales 37, 23 in an oblique 

 series upward and forward from front of anal. Body oblong, elliptical, 

 slightly heaviest forward; dorsal and ventral outlines similar, neither 

 much arched ; body not strongly compressed, its greatest thickness a little 

 less than its greatest depth; mouth very small, terminal, higher up 

 than usual, nearly in line of axis of body, the chin protruding beyond it; 

 width of mouth from angle to angle about equal to diameter of eye. 

 Lower jaw the longer, its teeth slightly directed backward; upper jaw 

 with its teeth directed slightly forward, shutting outside of the lower 

 teeth. Teeth pale brownish, somewhat unequal; lower teeth wedge- 

 shaped, broadest and nearly truncate at tip; teeth of upper jaw obliquely 

 truncate, slightly emarginate, the outer angle pointed and projecting; 

 about 8 teeth in outer row ; the mouth so closely shut that the inner row 

 can not be seen; eye small, high, and well back, its diameter contained 

 nearly twice in interorbital width, 3 in snout ; a groove in front of eye below 

 nostrils, about as long as diameter of eye ; 5 narrow grooves on cheek below 

 eye, extending from near mouth backward toward base of pectoral. 

 Height of gill opening slightly greater than diameter of eye, its lower 

 edge opposite middle of pectoral. Scales of body comparatively small, 

 not very rough; scales of belly somewhat reduced in size, arranged in 

 oblique series running downward and backward from pectoral region, 

 these forming a contrast in direction with scales of sides ; scales on caudal 

 peduncle without keel or spines, similar to those on rest of body ; scales 

 on posterior portion of sides slightly carinate, forming low ridges along 

 rows of scales. Gill opening surrounded by small scales and without 

 larger plates. First dorsal spine very robust, placed somewhat behind 

 eye, its height a little more than twice diameter of eye, the deep dorsal 

 groove as long as spine ; second spine short and slender, its length about 

 equal to diameter of eye; third dorsal spine wholly wanting; soft dorsal 

 rather high, its longest rays more than \ length of base of fin, If- in 

 head; anal similar, its base a little shorter, a few series of small scales 

 covering base of each lin ; caudal moderate, lunate, its depth from tip to 

 tip more than its length, and 1 J times in length of head. Caudal peduncle 

 subterete, deeper than broad; ventral spine slightly movable; pectoral 

 short, rounded, less than \ length of head. Coloration in spirits, dark 

 olive above, rather pale below, the skin between scales somewhat darker ; 

 scaly basal part of dorsal and anal abruptly black; membrane of these 

 fins yellowish, the tips dusky ; scaly base of caudal dark brown, the 

 medial part lighter brownish ; a lunate band at tip yellowish; pectorals 

 olivaceous. Rocky Islands off the west coast of Mexico, not common; 

 close to Xanthichthys ringem. Length 1 foot, (mento, having a long chin. ) 



Salutes mento, JORDAN & GILBERT, Proc. U. S. Nat. Mus. 1881, 228, Clarion Island, 

 Revillagigedo Group. (Type, No. 28387. Coll. Lieut. H. E.Nichols.) 



