the Ichthyolof/tj of Australia. 21 



of the dorsal and an odd one on the top of the trunk of the 

 tail ; whereas S. Gilberti has a series of twelve spots running 

 along the base of the spinous and soft dorsal to the caudal, 

 smaller, though darker, than those on the body. S. hexago- 

 natus has the same large spots along the dorsal \^\\hfaveatus^ 

 the same number of rays, and is further distinguished by 

 white dots on the body. Its second anal ray is stated to be 

 long and pointed. In B, Gilberti the second spine is deci- 

 dedly the strongest, but it scarcely exceeds the third one in 

 height. ^. ura has a rounded preoperculum, equably denticu- 

 lated on its margin. B. maculosus, as far as one can judge 

 from the short description, scarcely differs from ours in form, 

 except that it has two articulated rays fewer in the dorsal, and 

 one in the anal. There are no spots on its caudal, but, as 

 the only specimen noticed had been long kept in spirits, there 

 is no great weight to be attached to their absence. S. 

 bontoo has no spots on its fins. S, suillm has very strong 

 spines at the angle of the preoperculum, and no spots on the 

 dorsal. 



This comparison of the species which come nearest to 

 Mr. Gilbert's fish in the number of rays and general distri- 

 bution of colours, shows that the latter difiers as much from 

 any one of them as they do from one another ; and until an 

 examination of many individuals at their native haunts has 

 shown how far the rays may vary in the same species, and 

 what changes may take place in the patterns of colour at dif- 

 ferent seasons, it will be most convenient to assign a distinc- 

 tive name to the Port Essington fish. The analogy of the 

 nuptial dress assumed by the Salmonidce and other anadro- 

 mous fish may prepare us to expect a very considerable va- 

 riation in the brilliant tints of the Serrani on the approach of 

 the spawning season. It is certainly desirable that new spe- 

 cies should be proposed chiefly on the existence of some 

 tangible peculiarities of external form or of internal structure ; 

 but to do this properly, the ichthyologist requires to have 

 access to a well-filled museum. 



Dimensions. inches, lines. 



Length from intermaxillary symphysis to extremity of caudal . 12 3 



base of ditto 9 10 



anus 5 9| 



tip of gill-flap 3 7 



of pectorals 2 4 



ofventrals 1 10 



of caudal 2 5 



Height of the highest dorsal spine 1 4 



soft dorsal 1 4 



■ second anal spine 1 



— — — — poft anal 1 9 



