4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 124 



maxillary may have from one to several short canines on the largest 

 specimens, but absent on those from 100 to 140 mm in length; the 

 posteriormost row of teeth at side of dentary number from nine to 

 14 and the teeth apparently do not increase in number with increase 

 in length as found for N. u. ustus (see table 2). The profile of snout 

 forms an angle of 65° to 80° with that of lower jaw; distal margin of 

 caudal fin slightly rounded; middle spines of dorsal longest and the 

 sixth to eighth soft dorsal rays longest; the most dorsally located 

 branched ray of pectoral longest and notably longer than any pelvic 

 fin ray. 



The appearance in alcohol is shown in plate 1. 



Remarks. — Nicholsina ustus ustus occurs abundantly in the western 

 Atlantic Ocean from off New Jersey southward through Florida, 

 Yucatan, Venezuela to Brazil eastward to Bermuda and Cuba. 



Nicholsina denticulatus lives in the eastern Pacific Ocean and was 

 recorded from the Gulf of California and at Lobos de Afuera, Peru 

 (Schultz, op. cit., p. 129); additional Peruvian localities are: Lobos de 

 Tierra (USNM 128106, 128107, 128108, 128109, 128110), North 

 Chincha Island (USNM 128111), and Don Martin Island (USNM 

 128112). 



This new subspecies from the eastern Atlantic is close to N. u. ustus 

 of the western Atlantic. The color pattern of specimens preserved in 

 alcohol has faded so much that a comparison of the differences, if any, 



Table 2. — Number of gill rakers on first gill arch of Nicholsina ustus 



between the two subspecies is not now possible. Perhaps a comparison 

 of the color patterns of the two subspecies of living specimens might 

 reveal significant differences; however, no color photographs are 

 available. 



Two characters distinguish N. u. collettei from N. u. ustus at the 

 subspecies level. The number of gill rakers on the first gill arch of 

 ustus vary from 9 to 12, rarely 12 (average 10.53) (see table 2), whereas 

 those of collettei are 11 to 13 (average 11.93). There is an 84 percent 

 degree of separation if lines are drawn between 11 and 12 gill rakers 

 (table 2). The other main difference observed between ustus and 

 collettei is in the number of incisor-like teeth in the posterior row of the 

 dentary. In ustus the teeth are smaller anteriorly and the number 



