268 RECORDS OF THE AUSTRALIAN MUSEUM. 



On September 21st last, an Italian fisherman, plying his trade 

 at Narrabeen, brought us a fish which I recognised as Tetragonurus. 

 He remarked that though he had not noticed anything like it here 

 before, he was sure he had seen the same fish in the Mediterranean, 

 ofi" the Lipari Islands. 



The species is subject to considerable variation ; the number of 

 dorsal spines ranges from fifteen to twenty-one, the relative posi- 

 tion of the fins is not constant, while the colour is either brown 

 or black. 



While a detailed description is unnecessary, the following 

 general features of the New South Wales specimen may be 

 useful. 



D. xviii. 13; A. ii. 10; V. i. 5. 



Length of head 4 9, height of body 7 '3 in the total length. The 

 eye, which is 4-7 in the length of the head, occupies a more 

 posterior position than in the examples from Lord Howe Island ; 

 in these the length of the snout equals the diameter of the eye, in 

 mine it is fully one-half longer. 



The teeth in each ramus of the upper jaw number twenty-four, 

 in the mandible thirty. 



The dorsal fin commences well behind the end of the pectoral, 

 the distance between its origin and the tip of the snout being 

 contained 2 9 times in the total length. In the Lord Howe 

 Island examples, the corresponding figure is 3 7, and the fin 

 arises above the middle of the pectoral. In these the distance 

 between the last anal ray and the base of the caudal, is four-fifths 

 the length of the head, but equal to the head in my specimen. In 

 this also the ventral fin has a much more posterior insertion. 



Colour. — The colour is black, equally so below and above; when 

 fresh each scale was shot with violet and gold ; the iris is blue. 



Length of specimen 2.56 mm. 



In many fishes variations such as those aV)Ove indicated would 

 be held to constitute specific differences, yet if we examine other 

 descriptions of this fish we shall find even greater disparity. On 

 the other hand, complete intermediate conditions are described, 

 so that with T. atlanticus, Lowe, T. wilkinsoni, Macl., is correctly 

 sunk as a synonym of T. cuvieri, Risso. 



The range of the species may be stated as Mediterranean, 

 Atlantic (Madeira, and Wood's Holl, Massachusetts, U.S.A.), and 

 South Pacific (Lord Howe Island, and coast New South Wales). 



The following are the original references to the names bestowed : 

 Tetragonurus cuvieri, Risso, Ichth. Nice, 1810, p. 347, pi. x., 



fig. 37. 

 Tetragonurus atlanticus, Lowe, Proc. Zool. Soc, 1839, p. 79. 

 Ctenodax wilkinsoni, Macleay, Proc. Linn Soc. N.S.W., x., 1885, 



p. 718, pi. xlvii. 

 Tetragonurus wilkinsoni, Macleay, loc. cii., (2), i., 1886, p. 511. 



