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V. (Part 2.) Description 0/ Australian Fish. By John Richardson, M.D., F.R.S., Sfc, 



Inspector of Naval Hospitals, Haslar. 



Communicated June 25, 1839, March 10, 1840, and March 9, 1841. 



Cheikonectes politus (Nob.), Polished Cheironectes. 

 Ch. dorso bipinnato, corpore lavi, glabra, rubicundo, punctulato. 



Mr. Lempriere's list contains the following observation on the only specimen of this 

 fish in the collection. " Its colour is red, with spots, and all that I have seen were of 

 the same size. Nothing is known of its qualities as an article of food, as none of the 

 residents at Port Arthur have eaten it. An imperfect representation of it appeared in 

 Dr. Ross's 'Van Diemen's Land Annual' for 1835." This figure is certainly rude 

 enough, though it may be recognized by those who have seen the fish. It gives much 

 more development to the membrane of the first dorsal than is shown by our specimen, 

 but the edges of the fins in the latter have suffered a little by friction against other fish 

 contained in the same cask during the voyage from Port Arthur. 



The Cheironectes politus belongs to that subdivision of the genus which is character- 

 ized by the second and third nuchal rays, being connected to each other and to the back 

 by a continuous membrane so as to form a first dorsal. Two species only of this group 

 are mentioned in the ' Histoire des Poissons'. Of one of these, Ch. hirsutus, it is said, 

 " la scabrosite de la peau n'est pas tres-forte ;" and of the second, though it bears the 

 name of ' lavis,' " sa scabrosite, quoique forme'e de m^me, est un peu mains rude au toucher." 

 Politus is perfectly smooth to the touch and to the sight assisted by a common eye- 

 ■ glass ; and there are no membranous appendages visible on any part of the body. 



The height of the body, at the ventrals, is equal to one-third of the total length, and 

 behind the pectorals to one-fourth. The thickness at the same places is equal to about 

 half the height. The under jaw, when depressed, projects beyond the upper one, and 

 the forehead rises from the latter almost perpendicularly, soon however rounding off" 

 towards the nape in the segment of a circle. The small eye is situated not far from 

 the front, above and a little behind the angle of the mouth. The pectoral fin is sup- 

 ported by a rather long arm-hke base, and the very small round branchial aperture is 

 rather above and a little posterior to the axilla. The first ray of the anterior dorsal is 

 free, or connected to the second by a very minute fold of skin : it is comparatively 

 short, and originates at a short distance from the upper lip. The second ray is the 

 longest, and is connected to the slightly shorter third one by a thickish membrane, 

 which is prolonged backwards in a triangular slip that reaches nearly to the second 



VOL. III. PART II. T 



