96 DR. RICHARDSON'S DESCRIPTION OF AUSTRALIAN FISH. 



l8t Spec. 2nd Spec. 3rd Spec. 

 In. Lin. In. Lin. In. Lin. 



Height of third dorsal spine 1 10 1 11 2 



Height of soft dorsal 1 10 1 11 2 



Length of pectorals 2 10 2 8 3 3^ 



Length of ventrals 27 00 30 



Length of anal 16 00 19 



Length of caudal Ill 1 1 1 22 



Height of anal Ill 00 21 



Length from anal to extremity of caudal 4 9^ 5 6 



Length from dorsal to extremity of caudal 3 8 4 8 



Height of body at pectorals 40 00 47 



Thickness of body at pectorals 20 00 28 



Diameter of the orifice of the mouth 24 24 24 



Note. — The Cape specimens described by Cuvier were only seven inches long. 



Pl.\tycephalus tasmanius, Tasmanian Platycephalus. 



PI. tasmanius, osse preorbitari unidentato : orbitis inarmatis ; fastigiis cranii vix con- 

 spicuis ; preoperculo bispinoso, spind inferiori, longiori ; radiis pinneB dor si prima 

 septein vel octo spinosis ; secunda quatuordecem articulatis. 



The Platycephali abound in the Australian seas, and as the species resemble each 

 other closely, not only in general form, but also in their brown colours and the distri- 

 bution of the darker spots, it is difficult to find characters by which they maybe readily 

 known. Four New Holland ones are distinguished in the ' Histoire des Poissons,' from 

 each other and from their congeners, by the number and strength of the spinous teeth 

 on the infra-orbitar, the prominence of the cranial ridges, the size of the preopercular 

 spines, and other minute particulars. Our specimens agree nearly with the description 

 of P. bassensis, which was taken by Messrs. Quoy and Gaimard in Port Western, on 

 the opposite side of Bass's Straits to Tasman's Peninsula. That species, however, has 

 two blunt teeth on the edge of the preorbitar, while the four examples which we pos- 

 sess of tasmanius have but one projecting spinous tooth. Ours differ also in being 

 destitute of a tooth on the edge of the orbit. P. lavigatus also, from Port Western, 

 diifers more in having no tooth at all in the preorbitar, and in the inferior preopercular 

 spine being smaller than the upper one. In P. fuscus, from Port Jackson, the pre- 

 opercular spines are both of the same size, and the preorbitar has two rounded teeth ; 

 and in P. grandispinis there are not only three preorbitar spines, but the inferior pre- 

 opercular one is four times the length of the upper one, and reaches to the edge of the 

 operculum. It is possible that the size of the spines may vary with the sex or age of 

 the fish, but as they have been used for characterizing the species in the ' Histoire des 

 Poissons,' and we have no opportunity of comparing the actual specimens, no alterna- 



