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PROCEEDINGS OF THE NATIONAL MUSEUM. 



vol. 40. 



snout 2.64, conical; mouth moderate; maxillary 3.42, barely reach- 

 ing vertical from anterior nostril; nostrils close to eye, anterior 

 nostril larger, circular, provided with a flap posteriorly, posterior 

 nostril elongate, slit-like; interorbital 3.33, very slightly rounded; 

 preopercular border smooth except for a few weak denticulations near 

 upper angle and on horizontal margin; teeth in bands, long, slender, 

 with a slight constriction near tip; peritoneum silvery, with scattered 

 dusky spots. 



Scales unequal, those on middle of trunk larger than the others, 

 arranged in rows which are very distinct both upward and back- 

 ward and downward and backward; 22 transverse rows of scales 

 between opercle and end of last vertebra; head, belly, and vertical 



Fig. 1. — Ch^todon argentatus. (From the type. Natural size.) 



fins finely scaled. Scales subcircular, truncate at base; circuli 

 regular in arrangement, those in nuclear area enlarged or absent; 

 radial folds on basal portion of scale well developed, about 8 to 14 in 

 number; a moderately narrow area along apical margin of scale 

 with short radially arranged lines, each composed of a series of cones 

 or cone-like structures, slightly hastate in outline, truncate at tip, 

 appearing as if the apex of one had pierced the base of the one imme- 

 diately in front of it; the terminal cone in each row entire, forming 

 the series of spine-like structures along apical margin. 



Dorsal spines long and slender, fourth spine longest, 1.26 in head, 

 spines following this graduated backward; membranes of anterior 

 spines deeply incised; soft dorsal moderately low, evenly rounded; 

 caudal short, obliquely truncate; anal bluntly right-angled, second 



