476 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



strongly marked. The spot behind and above the pectoral fin covers 

 seven to nine oblique rows of scales, and extends upward to include 

 one or two rows above the lateral line. This spot in some specimens, 

 most notably in the young, is ocellated by a white ring, which sep- 

 arates the spot from the dark squarish blotches extending forward 

 and backward from the first dorsal fin. After an interspace about 

 as long as the snout plus the orbit, the pectoral spot is followed by 

 a dark bar extending. from the dorsal downward and backward to the 

 anal, and covering five to seven rows of scales. The sides of the 

 head and body show silvery reflections. The branchiostegal mem- 

 branes are mainly dark, but are margined with whitish. The linings 

 of the buccal cavity, except about the mouth, and of the upper half 

 of the branchial cavity, are dusky. The parietal peritoneum is 

 light purplish brown, punctulate with black, and underlain by sil- 

 very; the peritoneum is little darkened in young specimens. The 

 color of the fins, like that of the body, is widely variable; the first 

 dorsal is whitish or dusky, with the larger and distal part of its 

 spine, and the smaller and distal portion of its soft rays, blackish; 

 the second dorsal is constantly light, but the anal varies from dusky 

 to blackish anteriorly, and from whitish to dusky posteriorly; the 

 pectoral is whitish or dusky, the ventral dusky or blackish, with the 

 filament of its outer ray whitish. 



This species probably never reaches a large size. Our largest 

 specimen among 25 is a male, and measures only 65 mm. to the anus, 

 while females measuring 54 to 64 mm. to the anus have their ovaries 

 filled with ripening ova. C. argus is most closely related to C. dorsaMs 

 from northern Luzon, from which it differs in the larger scales, 

 lower dorsal, narrower snout, and in details in the form and in the 

 squamation of the head. 



Table of measurements in hundredths of length to anus. 



A Ibatross station 



Total I ongth, in mm 



Length to anus in mm 



Length of head 



Length of orbit 



Postorbital length of head 



Width of interorbital 



Width of suborbital 



Orbit to pretopercle 



Length of snout 



Length of upper jaw 



Depth of body 



Width of body 



Anus to anal 



Anus t o ventral 



Ventral to isthmus 



Height of second dorsal spine. 



Height of third dorsal ray 



Length of first dorsal base 



Length of interdorsal space. . . 



Lengt h of pectoral 



Length of outer ventral ray. . 

 Length of second ventral ray. 



5549 

 117 

 35 

 78 

 24 

 24 

 15 



26 

 33 



19.5 

 40 

 28 

 8 

 16 

 22 

 42 

 41 

 16 

 21 

 34 

 36 

 19 



'A small pseudocaudal developed. 



(argus, in reference to the eyelike spots.) 



