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 
hght 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 hight, 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. dorsalis 
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. 
Albatross Statouy. 22. -cseeee Seca eeee ce | teeee eee | 5549 5549 5135 5112 5549 
Totallength sin mime ashee a. > pace ere 196 | 186 171 1167 1 187 117 
Length tojanus in mim.ie o/s seece- eee 64 | 59 53. 5 54 65 35 
Lengthiothende-.eieoasuaeet cee ceh oes 80 | 87 Si 78 81.5 78 
hen gthnoharbitt soe: acs Sees a eee eee 24 21 22)” «| 23 23 24 
Postorbital length of head................. 24 23 24, 5 | 25 23 24 
Widthiofinterorbital::.-- 3.2. 2.222 sees. 2: 16 14 16 15. 5 16 15 
Width ofsuborbital-2- >. 2222.25 Sa aele LO) 8.5 9 9 9 9 
Oxrbititoypreopercle! 25s. 2-255, -eeeee eee 28 | 25 26 28 25 26 
MenethvoLsuout -<eoseeeeaee eee eee SEV | 33.5 34 31 37 33 
Length of appermjawis aecses. fe ceemen ee ee 20.3 18 19 20 18 19.5 
Depthioiibodyise sso.) py Pee Sen Se 46 39 43 42 41 40 
Width ofbodiy. snc es: tee eeere oo een ees ones 30 32 31 31 28 
ANUS: fOanal so. Jcseteciece. Aes 5 ere Saas MGR y 8.5 13 9 10.5 8 
ANUS CONVENES esc jae eee eee eee 19 | 17.5 18 16 17 16 
Mentral toisthms S22. eee cone eee 24 22 24 23 21 22 
Height of second dorsal spine.............- 46 52. 5 52 49 44 42 
Height of third dorsal ray.....-- Sees paisa 46 AS yi eee 42.5 41 
Length of first dorsal base.........-- Sepree'e Le oe 15 14 16 14 16 
Length of interdorsal space...............- 22 26 22 21 22.5 21 
engthion pectoral masse secon 36 36 38 | 36 32 34 
Length of outer ventral ray............... 36 36 38 37 30 36 
Length of second ventral ray............-. 20 21 22 21 21 19 
1A small pseudocaudal developed. 
(argus, in reference to the eyelike spots. ) 
