192 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



Genus RYPTICUS Cuvier and Valenciennes, 1829 



Body elongate, compressed; head moderately small, pointed; 

 mouth large, oblique; lower jaw projecting; maxillary rather long and 

 broad, with a narrow supplemental bone; teeth all small, in bands on 

 jaws, vomer, and palatines; opercle above posterior angle attached to 

 shoulder by membrane ; preopercle usually with 2 or 3 spines ; opercle 

 with 2 or 3 spines; gill rakers short and few; scales small, embedded; 

 dorsal continuous, highest posteriorly, with 2 or 3 spines; caudal 

 round ; anal similar to posterior part of dorsal, without spines ; ventral 

 small inserted in advance of pectoral; pectoral moderate, round. 



A single species, considered only subspecifically distinct from the 

 common Atlantic coast Rypticus saponaceus by Schultz and Reid 

 (1939, pp. 261-270), who revised the genus, is known from Peru. 



RYPTICUS SAPONACEUS BICOLOR (Valenciennes) 



Smecticus bicolor Valenciennes, 1855, p. 307, pi. 2, fig. 2 (original description). 



Rypticus xanti Meek and Hildebrand, 1925, p. 481, pi. 48, Panama Bay (descrip- 

 tion) . 



Rypticus nigripinnis Meek and Hildebrand, 1925, p. 482, Panama Bay (descrip- 

 tion) . 



Rypticus saponaceus bicolor Schultz and Reid, 1939, p. 263 (synonymy; dis- 

 cussion; list of specimens examined). 



Head 2.9 to 3.3; depth 3.1 to 3.75; D. II or III, 25 to 29; A. 17 or 

 18; P. 16 or 17; scales about 115 to 125 (too small to count accurately 

 in the small specimens at hand; too deeply embedded in the large 

 specimens to permit enumeration). 



Body compressed, its greatest thickness not more than half its 

 depth; back moderately elevated; profile from snout to nape nearly 

 straight to gently convex; caudal peduncle quite compressed, 2.2 to 

 2.7 in head; snout pointed, 5.3 to 6.4; eye 5.5 to 8.0; interorbital very 

 narrow, 12 to 16; mouth large, moderately oblique; lower jaw strongly 

 projecting, nearly or quite entering dorsal profile; maxillary extending 

 to or beyond posterior margin of eye, 2.15 to 2.7 in head; gill rakers 

 short, only about 4 to 7 on lower, and generally only 1 or 2 on upper 

 limb of first arch in addition to several very low rudiments on each 

 limb; opercle with 3 spines, and the preopercle with 2 spines; lateral 

 line complete, arched anteriorly, highest under dorsal spines, reaching 

 middle of side over about middle of anal; scales small, elongate, 

 shaped almost precisely like the sole of a sandal, without free edges, 

 embedded, especially in adult; dorsal with 2 or 3 rather strong spines, 

 scarcely longer than eye, the rays increasing gradually in length to 

 about the fourth to sixth from end of fin, the base heavily enveloped 

 in skin and flesh; caudal round; anal similar to posterior half or so of 

 dorsal; ventrals small, close together, inserted well in advance of 

 pectoral, about as long as snout and half the eye ; pectoral moderately 

 large, inserted well in advance of dorsal, broadly rounded, 1.4 to 1.8 

 in head, 4.3 to 5.3 in length. 



