22 MEMOIBS OF THE QUEENSLAND MUSEUM. 



passing gradually into soft rays. Caudal rounded or lanceolate, with 14 or 15- 

 principal rays, the outer ray above and below simple. Anal fin long and low, 

 with two weak spines. Pectorals short and fan-shaped. Ventrals inserted in 

 advance of the pectorals, close together, each of a spine and five rays, and without 

 accessory scale. Gill-openings wide ; gill-membranes partially united, free from 

 the isthmus; six branchiostegals ; pseudobranchi^ present; gills four, a slit 

 behind the fourth ; gill-rakers long and slender. Air-bladder present, small. No 

 pyloric cffica. A narrow subocular shelf. Skull narrow between and expanded 

 behind the orbits ; postorbital part evenly convex above ; occipital crest only on 

 the posterior face of the skull, which is long and oblique; no parietal crest; 

 exoecipital condyles separate; prootics forming a roof for the myodome; basi- 

 sphenoid present. Foramen in hypercoracoid ; radials rather broad and flat, two 

 on the hypercoracoid and two on the hypocoracoid. Vertebra? 29 (10 X 19)^; 

 precaudals with parapophyses from the fifth; three ribs sessile, five on para- 

 pophyses ; epipleurals on ribs. 



The Opisthognathidce, though weak in point of numbers, forms a most 

 interesting family of trachiniform percoids; it consists of fishes of small or 

 moderate size, inhabiting rocky and coralline bottoms within the tropical and 

 temperate zones. Its distribution is peculiar, no species having so far been 

 recorded from the Mediterranean nor the Eastern Atlantic, nor from any of the 

 Pacific Islands, nor the West Coast of the Americas, except the Gulf of California, 

 where an isolated colony, comprised of five species, exists. The extreme limits of 

 their polar range lie between lat. 40° N., where Gnuthypops hopkinsi has been 

 taken off Misaki, Japan, and lat. 34° S., where Merogymnus jacksoniensis is 

 found. These fishes are everywhere of rare occurrence, many of the species being 

 only known from the single example described. The "Smilers," to give them 

 the local vernacular name bestowed upon them, so a friend tells me, ''because of 

 their fine open countenance," are essentially carnivorous and rock-loving fishes, 

 delighting in boulder-strewn shoals and coral reefs at a moderate depth. Hence 

 we find that in America as here many of the species are only known from off- 

 shore snapper grounds and similar localities, where they are occasionally taken 

 by hand-line in company with more valuable fishes or even from the latter when 

 captured disgorging them. The species vary greatly in coloration, some of them, 

 such as my Merogymnus eximius, being arrayed in a livery of most gorgeous 

 splendor, while others, as my Gnathypops inornata, are soberly clad in uniform 

 brown. One of our species, G. maculata, is said by the pearl-fishers to scoop holes 

 in the sand among the sea-fan forests of our tropic seas, from which it sallies 

 forth to pounce upon a passing prey, returning again to its lair after each 

 excursion. Regarding this habit Mr. W. H., Longley, from personal observation 

 when "equipped with a diving hood in the unknown world of coral labyrinths at 

 the bottom of the sea," gives some interesting information, which may advan- 

 tageously be reproduced here.^" He writes: — "Gnathypops mirifrons prepares 



* VertebraB 27 to 34, fide Jordan & Evermann, ut supiKi. 

 " American Museum Journal, xviii, February 1918, p. 81. 



