Jordan and Evermanu. Fishes of North America. 3175 



opercle; mouth horizontal, lower jaw projecting; lips thick, the lower 

 without frenum, folding over the upper at their union; premaxillary pro- 

 tractile; maxillary small, nearly vertical in position, and almost hidden 

 by the large preorbital; teeth on both jaws, in 2 series, the outer a single 

 row of 24 canines, largest in front, growing smaller posteriorly, the inner 

 series villiform; all of the teeth with brown-colored tips: gill-membranes 

 free from isthmus; branchiostegals 5; gill-rakers on first arch 9, short, 

 blunt, far apart. Body covered with large scales; cheek, opercle, inter- 

 opercle, subopercle, and occipital portion of head with small scales; 

 ventral part of head, preorbital area, snout, and anterior part of inter- 

 orbital space naked; one row of scales extending on bases of dorsal and 

 anal fins; scales of body weakly-ctenoid; scales of head smooth; lateral 

 line interrupted on the nineteenth transverse row of scales, beginning 

 again 3 scales lower down and 2 scales in advance of where it left off and 

 extending to base of caudal ; first dorsal spine short and slender, others 

 gradually longer and heavier, posterior spine longest; each spine with a 

 rather stiff distal, ray-like attachment, the anterior edge of which pro- 

 jects above the membrane of fin; tips of fourth and fifth rays of dorsal 

 uniting 1 to form a thread-like filament about as long as the diameter of 

 orbit; dorsal, when depressed, extending on caudal one-third its length; 

 first anal spine shortest, others growing gradually longer and heavier, 

 the last 2-J times as long as the first; spines with distal attachments simi- 

 lar to those of dorsal, third and fourth rays longest, united at their tips, 

 forming a slender filament; tip of anal extending a little farther posteri- 

 orly than that of dorsal ; caudal rounded ; tip of pectoral rounded ; ven- 

 trals located slightly posterior to base of pectoral, extending to vent, 

 outer ray longest, ending in a filament. Color dark, an oblong brownish- 

 black spot at base of each scale on side of body, the spots growing less 

 distinct above the pectoral; membranes of dorsal, anal, and caudal with 

 small spots, these more distinct and regularly arranged on soft parts of 

 dorsal and anal; pectoral and ventrals without spots. 



Young individuals have a brownish-black spot at base of caudal and on 

 side of body at tip of pectoral; a less distinct spot at upper edge of gill- 

 opening and also below posterior end of base of dorsal. The darker of 

 these spots are sometimes faintly indicated on the larger individuals. 

 Morelos, Mexico. (Jordan & Snyder.) 



Known only from Rio Ixtla at Puente de Ixtla, Morelos, Mexico. (Type, 

 No. 6150, L. S. Jr. Univ. Mus. Coll. Jordan & Snyder.) 



Heros istlanus, JORDAN & SNYDEIJ, Bull. U. S. Fish Com. 1899 (1900), 144, Rio Ixtla, 

 Morelos, Mexico. 



Page 1542. After Xeetroplus nicaraguensis, Gill & Bransford, insert: 

 1951 (a). XEETROPLUS CARPIXTIS, Jordan & Snyder. 



Head 2g ; depth 2 ; depth of caudal peduncle 6 ; eye 5 in head ; snout 2 ; 

 interorbital space 2|; longest dorsal spine 21; ray 1; longest anal spine 

 2, ray H; length of pectoral 1^; ventrals 1; caudal 1; D. XVI, 10; A. 

 V,8; P. 15; scales 26-17,7 on caudal peduncle. Body compressed, deep- 

 est part above ventrals ; dorsal outline straight from tip of snout to a 



