PHILIPPINE MACEOUROID FISHES — GILBERT AND HUBBS. 425 



ANALYTICAL KEY TO THE SUBGENERA AND SPECIES OF COELOUHYNCHUS. 1 



A 1 . Teeth in the lower jaw biserial or nearly so, at least on the sides; scales 



little strengthened on the weak ridges of the head ; subopercle angulated 



at posteroventral angle, but without a distinct flap. 



B \ Teeth biserial in both jaws ; anus remote from anal, and preceded by a 



single large naked fossa covering a glandular body not supported by a 



rod of cartilage ; scales well imbricate, armed with spinules on strong 



divergent carinae ; anterior portion of eyeball scaled ; one Japanese 



species abyssicola 



macrochir. 

 B 2 . Teeth in a cardiform band in upper jaw ; anus posterior in position, im- 

 mediately in advance of anal ; anus preceded by a long cylindrical 

 organ with a dilation immediately before the anus, and another, before 

 the ventral fins, supported by an arched rod of cartilage connected 

 with the pubic bone ; scales poorly imbricate, armed with spinules 

 arranged in quincunx order ; eyeball wholly naked ; three East- 

 Indian species quincuncia. 



a \ Underside of head naked ; five or six series of scales between lateral 

 line and origin of second dorsal ; distance from anus to base of 

 ventral in head, 1.8 to 2.3 ; distance from anus to isthmus in head, 



1.15 to 1.32 argentatus. 



a 2 . Underside of head scaled ; four series of scales between lateral line and 



and origin of second dorsal ; distance from anus to base of ventral 



in head, 2.4 to 3.5. 



ft 1 . Kami of mandibles scaled ; front of premaxillaries below middle of 



nasal fossa ; distance from anus to isthmus in head, 1.32 to 1.6 ; 



numerous proportions of fins and of parts of head generally like 



those of C. argentatus (see p. 445) quincunciatus. 



b 2 Rami of mandibles nearly scaleless ; front of premaxillaries below 

 posterior nostril ; distance from anus to isthmus in head, 1.6 to 

 2.0; numerous proportions of fins and of parts of head different 

 from those of C. argentatus and C. quincunciatus (see p. 445) 



thompsoni. 



A 2 . Teeth of both jaws in villiform bands (sometimes. reduced in the lower jaw 



to scarcely more than three series in the subgenus Oxygadus) . 



B 1 . Subopercle with posteroventral angle rounded; snout little produced; 



physiognomy much as in Quincuncia, the ridges of head weakly 



armed ; anus never in advance of normal position just before anal fin ; 



height of first dorsal fin less than postrdstral length of head ; a closely 



related group of six species known only from the Atlantic Ocean and 



the Eastern Pacific 1 coelorhynchus. 



a\ Spinules on scales arranged in quincunx order, without a median 



series; no prominent median occipital scaly ridge; species of the 



North Atlantic. 



b\ Median scale of terminal rostral tubercles not so strong as the lateral 



pair ; scaleless ventral fossa elongate, one-third as wide as long. 



&. Scales with smaller spinules ; no prominent spot on first dorsal ; no 



dark barks on body ; a species of the eastern Atlantic 



coelorhynchus. 



1 We include all of the known species with the exception of C. labiaius (Koehler), the 

 original description of which is not available to us. 



