FISHES 1365 



state by the early rains moistening the surrounding 

 clay; and when the pools and rivers once more at- 

 tain their wonted depth, the Lepidosirens emerge 

 from their nests, seek the water, breathe by means of 

 their gills, and otherwise lead a true aquatic exist- 

 ence. Another fish, the Ceratodus or "Barramunda" 

 of Australian rivers, possesses a similarly modified 

 air-bladder, and is thus enabled to breathe inde- 

 pendently of its gills. 



With such a combination of the characters of land 

 and water animals, it is little to be wondered at that 

 the true position of the mud-fishes and their neigh- 

 bors in the zoological scale should have formed a 

 subject for much discussion. They appear, how- 

 ever, to be true fishes, and not amphibians (or frog- 

 like animals) ; and they therefore may legally oc- 

 cupy a prominent position among the oddities of 

 their class. 



Other curious beings included among the fishes 

 are the so-called globe-fishes (Diodon, etc.), which 

 derive their name from their power of distending 

 their bodies with air at will; and their bodies being 

 usually provided with spines, they may be judged 

 to present a rather formidable front to any ordinary 

 adversary in their expanded condition. Then also 

 we have the curious trigger-fishes (Balistes), so 

 named from the prominent pointed spine in front 

 of the first back-fin; this spine firmly holding its 

 erect position until the second spine or fin-ray be 

 depressed, when the first spine is released by mechan- 

 ism resembling that of the trigger of a gun. The 

 obvious use of such an apparatus is clearly of a de- 



