WESTERN ATLANTIC PERCOPHIDID FISHES — GINSBURG 629 



Bemhrops examined the mandibular rami are more or less scaled, but 

 the area between them is naked.) Chriomystax fm'ther differs in 

 having 18 anal tsljs, instead of 24 as in Chrionema chryseres. The 

 latter character ordinarily, in fishes in general, would not be deemed 

 of generic importance. However, in the species of the two genera 

 here treated the number of anal rays varies intraspecifically and differs 

 interspecifically withm comparatively narrow limits. In eight species 

 of Bemhrops and two of CJiriomystax the total range is 16-19 (see table 1 

 and the counts of extralunital species, p. 632). Consequently, it seems 

 that in this family this difference sometimes indicates a higher degree 

 of divergence than that of species. 



Chrionema chryseres, the type species of its genus, differs in three 

 other characters : The gill rakers are fewer and those at both ends of 

 the arch are much reduced, in the form of low tubercles, while in the 

 two species of Chriomystax in addition to being more numerous in 

 total count, those at the ends of the arch are slenderer and longer, 

 not in the form of tubercles; the bands of teeth are conspicuously 

 wider in C. chryseres; and it is a much rougher fish, the scales being 

 more strongly ctenoid. However, any one or all three of these 

 differences might possibly be governed by growth, the single available 

 specimen of C. chryseres being considerably larger, 181 mm. in standard 

 length, while the two species of Chriomystax examined are 29-55 mm. 

 in the same length. 



In the original account of his Chrionema, Gilbert (1905, pp. 645-646) 

 included two species — chryseres, the genotype, and squamiceps. The 

 latter species is near Chriomystax squamenium in its structural char- 

 acters and should be placed in the same genus with it. The differences 

 between these tv/o congeneric species are discussed below. 



Chriomystax squamentum, new species 



Description: D VI; 15-16.Al8.P21-22.Sc 55-61. GR 7-9 + 20-21. 

 Dorsal rays usually 15, sometimes 16. Anal rays constantly 

 18. Pectoral rays 21-22. (The uppermost pectoral ray has a 

 slight ridge along its upper aspect that may be separated cleanly 

 when some pressure is applied to it with a dissecting needle, and it 

 then appears like a very thin distinct ray. However, the ridge does 

 not seem to be separated basally from the ray. It apparently does 

 not represent a separate ray and was not included in the count of the 

 pectoral rays.) Gill rakers at both attached ends of the outer arch 

 slender, graduated, not in the form of short stumpy tubercles, except 

 one short gill raker, abruptly shorter than the others, intermediate in 

 development between a gill raker and a tubercle, occasionally present 

 at either end of the arch; gill rakers, including the short one when 

 present, 7-9 + 20-2 1 or 27-30 in total number on both limbs. Anterior 



