PHILIPPINE MACROUROID FISHES—GILBERT AND HUBBS. 445 
margin of the suborbital region, is dark, showing through the thin 
outer wall of the cavity; the rami of the mandibles are dark. The 
gular membrane has a ground color of silvery white, especially on the 
sides where covered by the mandibular rami, but is darkened by 
punctulations or a diffused dark expansion of the chromatophores. 
The branchiostegal membranes are dusky ventrally, but, together 
with the opercular membranes, are margined with light on their sides, 
just behind the submarginal blackish area of the branchial cavity, 
which shows through the opercles to the exterior; the roof of the 
branchial cavity is dark; the walls of the buccal cavity are light; 
the parietal peritoneum is blackish, underlain with silvery. The 
vertical fins and the pectoral are dusky; the dorsal spine is blackish; 
the ventral fin rays are ight, with dusky tips and dusky bases in 
some specimens. 
C. thompsoni differs from C. argentatus in much the same manner 
that C. guincunciatus does; the scales are larger, being in but four 
series, instead of five or six, between the lateral line and the origin 
of the second dorsal fin; the underside of the head,! and the antero- 
lateral region of the snout above, are scaled, instead of being mostly 
naked; and the gular membrane is punctate, rather than transversely 
striate. From both of the other species (. thompsoni differs in the 
more posterior position of the front of the premaxillaries, which lie 
below the posterior nostril, instead of below the middle of the large 
nasal fossa. Further differences between C. thompsoni and C. quin- 
cunciatus consist chiefly in the various proportions. These differ- 
ences are tabulated in the following comparison; further differences 
between thompsoni and argentatus are also indicated. 
Comparative table. showing the differences in certain proportions between the 
species of the subgenus Quincuncia. 
C. argentatus. | C.quincunciatus.| C. thompsoni. 
MMS tO basejot vembralimihead. 45.2 oc: <<< ccceana-co-s 158) Ole 2.4 to3.2 2 TeaitO1se 
PRMUSHORStM MAS iin heads awe ame oe ee RE ey 1.15 to 1.32 1.32 to 1.6 1.6 to2.0 
Preocular length of snout in head._.................-.-- 2.4 to 2.8 2.3 to 2.55 2.1 to 2.2 
Preoriiengih ofsnouhimheades.-- 22.2) leon ese 2.9 to3.8 2.8 to 3.3 2. 22 to 2.35 
Width of snout at anterolateral angles in distance anterior] 
UELGT Cts See ape oth nee eins SR BREF RENIN BK ee 1.0 to1.3 ey COS 1.4 to 1.55 
OrpuiAmesMo te teste eee 18 Wee URC i en 20 sae 1a GOle75, 1.6 to1.9 1.8 to 1.95 
OROUPIDEDOSLON Dital soe ce ales ERE ty NN a ea lea, bOrlert ro bona 1.05 to 1.2 
IMteraroiialnmupostOnbubal ="... cana aye yan 1.4 to1.7 1 tot 1. 23 to 1.4 
Suiborbitalinipostorpi tal se 28 Oe ee a ae 2.9 to3.4 Zot tOvdsl 2.5 to3.0 
Distance between occipital ridges in interorbital....._.. 2.6 to3.4 2.9 t03.3 2.4 to 2.65 
Wy HE weay Thal Juve G Fe eae Seen eas 9 OL oN UGE eS tease oa 2.8 to3.3 Boor wOlo. t 4.05 to 4.35 
Pectoral fin in head.. 2.2 to 2.9 2.4 to 2.65 3.05 to 3.3 
Outer ventral ray...... 2.6 to3.3 3.0 to 3.2 3.6 to4.3 
Second) ventral ray-22.c44). 6 sca So. 3.3 to4.2 3.75 to 4. 2 4.65 to 5.1 
Barbe] in postorbital 2.6 to 4.2 2.3 to3.0 3.4 to 4.6 
1 With the exception of the mandibular rami, which are nearly naked in thompsoni, 
but scaled in qwincunciatus. 
