146 DR. RICHARDSON'S DESCRIPTION OF AUSTRALIAN FISH. 



been no development of a suborbitar lip, and little of the labial is covered by that bone. 

 The broad and deep, finely scaly cheek comes forward to the labials, and is bounded 

 both below and behind by the smooth preoperculum. The upper limb of this bone is 

 very narrow and inclines backwards. The lower limb is broader and runs forward to 

 beneath the labial at the distance of two diameters of the orbit beneath the eye, and 

 curves gradually behind into the rounded angle of the bone. The disk of the bone is 

 neven, but not rough. The anterior edge of the first suborbitar is even, the posterior 

 ones are very narrow. They are all scaleless, as is the whole top of the head, as well 

 as the labials, lips, gill-membranes, and interoperculum. The bony operculum is twice 

 as high as wide, and is terminated posteriorly by two rounded lobes, with a deep semi- 

 circular notch between them. In the recent fish the notch is tilled up by thick mem- 

 brane, which also narrowly edges the lobes. The surface of the operculum is clothed 

 with small scales that terminate irregularly a little way from its posterior margin ; a 

 few small scattered scales exist on the suboperculum, which is narrow, and does not 

 project beyond the operculum. 



The humeral chain of bones is covered with naked skin, except that there is an oval 

 scaly patch between the limbs of the supra-scapular, and an irregular cluster of scales 

 on the reverted plate of the coracoid immediately above the pectoral fin. The edge of 

 this process of the coracoid is obliquely and irregularly crenated, the crenatures cor- 

 responding to fine furrows on the surface. In the axilla of the fin there is a broad, 

 scaleless, triangular plate. The axillae of the ventrals are also scaleless, and there does 

 not appear to have been any scaly process between these fins. The scales covering the 

 body are small and oblong, truncated or cut concavely at the base, and narrower than 

 the uncovered edge, which is flatly curved. There are from five to ten or eleven very 

 short and almost obsolete, slightly diverging furrows on the base. The lines of struc- 

 ture parallel to the lateral edges of the scale are rather strong, and the uncovered por- 

 tion, protected by a thick mucous epidermis, appears to be dotted, and even toothed on 

 the margin in the dried fish, but this roughness disappears on maceration. Each scale 

 is imbedded in a strong sac of the very tough skin. The scales are smaller towards the 

 anterior part of the back than on the sides, and become again very sensibly smaller 

 below the level of the pectorals. They are smallest before the ventrals, but behind 

 these fins, on the centre of the belly, there is a stripe on which the scales are as large 

 as on the sides, and more of their surface is exposed. The scales end on the nape by 

 a transverse line even with the upper end of the preoperculum. 



The lateral Une has a curve corresponding to that of the back from the supra- scapu- 

 lar till it passes the dorsal tin, it then passes horizontally through the tail to the caudal 

 fin, on which it is prolonged to within one-third of its margin, this portion of it being 

 slightly deflected. It is composed of a series of tubular elevations, of which there are 

 fifty in the arched part of the line, and about twenty from thence to the base of the 

 caudal. None of the tubes are branched. 



Radii.— Br. 5 - 5 ; P. 18 ; V. 1|5 ; D. 12112 ; A. 3|12 ; C. 15f. 



