DR. RICHARDSON'S DESCRIPTION OF AUSTRALIAN FISH. 123 



TT • 1 /• 1 • 1 1 • Inches. Lines. 

 Height 01 third dorsal spine 1 g 



Height of sixth ditto ' 1 2 



Height of first and seventh 1 ji 



Height of nineteenth 5 



Height of soft dorsal and anal ] Q 



Length of caudal lobes 2 3\ 



Depth of caudal fork 1 2 



Depth of body at pectorals 1 9 



Thickness of ditto Oil 



Length of oesophagus and stomach 5 6 



Length of longest pyloric caecum 2 



A second specimen, preserved in brine, has been more recently received, which re- 

 sembles the preceding one strongly, but it has only six spurious pinnules above and 

 below on the tail, and the lateral line curves under the fourteenth spine. The dorsal 

 spines are injured, but they appear to have been a httle lower than those of the speci- 

 men described above. I am not inclined to consider it as specifically distinct. 



DajausDiemensis, Tasmanian Dajaus. — Dajaus Diemensis, Rich., Zool. Proc. March 10, 

 1840; Jenyns, Zool. Beagle. 



D. rostra fer^ truncato vix prominente. 



Radii.— Br. 6 - 6 ; P. 15 ; D. 4 - 10 ; A. 3|12 ; V. I|5; C. ]4|. 

 The Mullets resemble one another so closely, that at first sight it appears diSicult to 

 detect distinctive characters ; there are, however, differences in the proportions of the 

 head and other parts, in the form of the lips, suborbitars, eye, tongue and palate, and 

 in the various distribution of rough plates on the interior of the mouth, which, by their 

 combinations, furnish characters for the discrimination of species. There is also some 

 variety of internal structure, such as in the lining of the intestinal canal, the form of 

 the stomach, and the number of pyloric caeca in different species. The Van Diemen's 

 Land Mullet here described presents a group of characters not to be found in any of 

 those which are enumerated in the ' Histoire des Poissons,' and it may be readily 

 known from them all, at first sight, by its smaller scales and more numerous rays in 

 the anal fin. It is furnished with plates of tine teeth on the palate and vomer, on 

 which account I have placed it in the subgenus Dajaus. It is true that these teeth are 

 small, and the plates, before the mucus is cleared away from them, appear scarcelv to 

 differ from the rough patches in the interior of the mouth of some acknowledged Mul- 

 lets, one of which, Mugil saliens, has even the vomer rough. But when the roof of the 

 mouth is well washed, the vomerine and palatine teeth of Dajaus Diemensis are distinctly 

 visible to the naked eye, being similar to, and nearly as long as, those on the jaws ; and 



' The tips of the fourth and fifth spines are mutilated in the specimen. 



r2 



