DR. RICHARDSON'S DESCRIPTION OF AUSTRALIAN FISH. 97 



live remains but to describe the Port Arthur fish as distinct, though the differences 

 they present are certainly very slight. 



Colour. — The snout, sides of the head, gill-covers and body are marked at pretty 

 regular distances by roundish and crescentic dark umber-brown spots, which are 

 smallest and most crowded on the head, and larger on the sides, where the upper brown 

 tints meet with the pale colour of the under surface ; these large spots are continued 

 from behind the pectorals in a regular series to the caudal fin. There is a broad sub- 

 terminal band of the same colour on this fin, but it is continuous only on the lower half, 

 being indicated above by several rows of roundish, irregular, and paler spots. There 

 are many small spots on the pectorals, most distinct towards the bases of the upper rays, 

 and also a few pale spots on the rays of the dorsals. 



Form. — The lateral hne is marked by a series of tubes, which turn downwards and 

 are narrower at the tips ; it runs straight from the supra-scapular to the extremity of 

 the caudal, passing between the eighth and ninth rays. The scales are strongly ciliated. 



Rays.—B. 7 - 7 ; D. 1|- 6|- 14, or 1|- 7|- 14; A. 14; V. 1|.5 ; C. 12f ; P. 11 

 and VI. 



The fin-membranes, especially of the dorsal and pectoral, are delicate. The first 

 dorsal spine is short, and forms with its membrane a separate fin. The first ray of the 

 posterior dorsal is simple but articulated at the tip ; and it is longer than the succeed- 

 ing ones, which are branched and diminish successively in height. The distance be- 

 tween the eyes does not much exceed half the diameter of the orbit, being less than in 

 fuscus or grandispinis. A single short, subulate tooth projects over the limb of the 

 maxillary bone, from below the notch of the anterior suborbitar, and there is an even 

 ridge continued backwards from it to the angle of the preoperculum. This ridge, 

 though conspicuous enough in the skeleton, barely shows in the recent fish, and has 

 no spinous points. The under edge of the preorbitar is slightly undulated near the 

 spine, but emits no second tooth. The mesial ridge of the snout is not continued to 

 the interorbitar space, though in the skeleton a slight elevation is perceptible as far as 

 the anterior third of the orbits. There are no teeth on the circumference of the orbit, 

 but its upper edge is raised and acute. The temporal ridge is short and inconspicuous ; 

 a minute spine can be detected on it in the skeleton. 



In the general smoothness of the head, and the existence of mere indications of cranial 

 crests rather than their actual prominence in the recent fish, the species approaches near 

 to the IcBvigatus of Port Western, but there are differences in the number of rays in the 

 first dorsal, and in the suborbitar and preopercular spines as mentioned above. The 

 operculum of tasmanius ends in a triangular, acute but not spinous point ; and beneath, 

 and projecting considerably beyond it, is the rounded, thin, cartilaginous, scaly flap of 

 the suboperculum. The lower preopercular spine measures one-sixth of the length of 

 the head, and is longer than the upper one, but not in an equal degree in all the speci- 

 mens, nor on both sides of the head. It is longest in all of them on the right side, and 

 in one example reaches nearly to the edge of the operculum, being in that case twice the 



VOL. III. P.\RT I. 



