Animals Before Man 



Associated with the "fishes " just described, 

 during the latter part of their career, were 

 others more like those of to-day ; in fact, one or 

 two of them are represented by living species. 

 Such are the so-called lung-fishes,* the Aus- 

 tralian Ceratodus, the African Protopterus, and 

 his South American cousin, Lepidosiren, the 

 last two also known as mudfishes, from their 



Ceratodus forsteri, a modern lung-fish from Australia. 



habit of passing the dry season ensconced in a 

 mass of dried mud. These form the subclass 

 Dipnoi, whose members present some resem- 

 blances to the amphibians another instance 

 of the interrelation of living beings. Owing 

 to this, as well as to their great antiquity, these 

 fishes are of special interest, and their struc- 



* So named because the air-bladder, which is present in many 

 fishes, in this group opens into the gullet, and is so modified as to 

 serve the purposes of a lung. 



98 



