PHILIPPINE MACROUROID FISHES GILBERT AND HUBBS. 



475 



cent-shaped naked region, with the convex side just in front of the 

 occipital scute. This scute is less modified than in related species ; it 

 bears five to seven carinae not much stronger than those on the scales 

 of the body ; behind this scute the scales are rather small ; a similar 

 scute, even less modified, occurs in some specimens on the mid-dorsal 

 line between the main scute and the origin of the first dorsal ; a scute 

 with a strong median keel is sometimes developed at the anterior end 

 of the lateral line. The squamation of the region between the occi- 

 pital and postorbital ridges also differs conspicuously from that of 

 the other species: the lower two-thirds of this area is covered by 

 two or three subequal rows of scales, bearing as many as 11 divergent 

 carinae, while the upper third is covered by scales mostly of greatly 

 reduced size. The region below the orbit and the larger part of the 

 anterolateral region of the upper surface of the snout are covered 

 by prickle-like scales. The under side of the head is wholty naked. 



The first dorsal spine is sharp; the second spine in some speci- 

 mens ends in a short, fine filament; its length is variable, about 

 equal to the postrostral length of the head. The base of the first 

 dorsal is contained 1.3 to 1.7 times in the interdorsal space, and 

 1.4 to 1.8 times in the postorbital length of head. The second 

 dorsal fin is low anteriorly, its first rays being contained from 4 

 to 6 times in the length of the orbit. The origin of the anal fin 

 lies below the middle or the anterior half of the interdorsal space. 

 The outer ventral ray ends in a filament, which, like that of the 

 dorsal spine, is sometimes compressed distally. The second ventral ray 

 reaches almost to the origin of the anal fin. The wide variation exist- 

 ing in the length of the fin-rays is apparently not sexual, as was 

 demonstrated in those species with elevated dorsals (as C. velifer). 



Table to show variation of fin-rays in male and female specimens. 1 



Males. 



Females. 



Second dorsal spine in head . 



Third dorsal ray in head 



Pectoral fin in head 



Outer ventral ray in head . . . 

 Second ventral ray in head . 



1.5 to 1.85 1.6 to 2.0 



1.7 to 1.9 1.8 to 2.2. 



2.2 to 2.5 2.1 to 2.65. 



2.1 to 2.8 2.25 to 2.7. 



3.45 to 4.0 3.4 to 4.25. 



1 Five males and four females were measured, including both sexes from southern 

 Luzon and .from off Jolo Island. 



The color of G. argus is more variable than that of any other 

 species of the group examined. The ground color varies from light 

 yellowish to dark brown. The region between the anus, ventrals, and 

 isthmus is blackish. The dark specimens are from China Sea, 

 while the lighter ones were dredged in the vicinity of Jolo Island, 

 and in Davao Gulf, off the southern coast of Mindanao (other dif- 

 ferences are not evident between the northern and the southern 

 specimens). The dark markings are very indistinct in certain speci- 

 mens, both of the light and dark types, while in others they are very 



