DR. RICHARDSON'S DESCRIPTION OF AUSTRALIAN FISH. 103 



a quadrantal arc, and from thence to the heads of the maxillary bones it descends in a 

 straight line. The caudal fin is deeply forked, and springs from the slender tail in a 

 some^vvhat similar manner to that of the common Mackerel. The head is compressed ; 

 the snout narrow. On the anterior angle of each orbit, immediately over the nostrils, 

 there is a blunt projection which varies in size in the two specimens, forming in the 

 one belonging to the British Museum a conspicuous horn, but being in the other 

 scarcely more distinct than the end of the maxillary bone, which forms a knob on the 

 side of the snout in the dried fish. The intermaxillaries have a slight protractility, 

 their pedicles ghding between and beneath the maxillary knobs. The gape is small, 

 the angle of the mouth not extending more than half way to the orbit. Narrow belts 

 of short villiform teeth arm the intermaxillaries and lower jaw, lying considerably 

 within the tumid hps. The maxillary bone hes well behind the orifice of the mouth, 

 its tip alone touching the angle of the gape. The nostrils pierce the posterior half of a 

 triangular membrane, the hinder orifice being close to the orbit, and rather above its 

 centre. The suborbitar bone is more restricted than that of Ch. carponemus, and is 

 covered by smooth skin which is perforated by many mucous pores. The moderately 

 large eye is situated near the profile of the forehead, and fully its own diameter above 

 the lower Umb of the preoperculum, which is on a line with the pectoral fin and corner 

 of the mouth. The inferior edge of the preoperculum is distinctly crenated, though it 

 is probable that the crenatures are not visible in the recent fish ; the rounded angle 

 and the vertical upper limb have smooth edges. The bony operculum ends in a thin, 

 flat, acute point, above which there is a wide rounded notch, occupied by scaly mem- 

 brane, and terminated by a shorter point. The flexible and scaly tip of the suboper- 

 culum projects beyond the operculum. The whole gill-flap is edged with smooth mem- 

 brane, and has an obtuse triangular form, its apex passing a little beyond the base of 

 the upper pectoral ray. I was able to count five gill-rays in the Haslar specimen, and 

 there may be a sixth. 



The eight upper rays of the pectoral have branching tips, the six lower ones are 

 simple ; of these the second projects backwards to the anus, and is one-third longer 

 than the adjoining rays above and below ; the rest diminish in succession, both towards 

 the first and last ray, but the inferior ones more rapidly, so that the lowest has only 

 one-fourth of the length of the longest. The ventrals are attached beneath the posterior 

 third of the branching pectoral rays, and are pointed ; the spine has a flexible tip, and 

 is one-third shorter than the soft rays which immediately follow it. The dorsal com- 

 mences over the vertical limb of the preoperculum ; its fourth spine is by much the 

 tallest, and its height rather exceeds the length of the space between its base and the 

 pectoral fin ; the three spines anterior to it, though strong, are very short ; the fifth 

 is one-sixth shorter than the fourth, after which the rest decrease very slowly, so that 

 the seventeenth is about half the length of the sixth, and twice as long as the second. 

 The anterior spines are much compressed, and are stronger than the posterior ones, 



