148 ON CERATODUS FORSTERI. 



teeth fit eacli other like the teeth of a common rat-trap, so that 

 they form a powerful grasping apparatus. Each fish has four of 

 these teeth. 



The microscopic structure of these teeth very strongly resemble 

 those of the old Palaeozoic fish — Psammodus, Ctenodus, Dipterus, 

 Cheirodus, and Conchodus. The fossil teeth attain a much larger 

 size than the recent, many having been found more than three 

 inches in length. Besides these remarkably formed teeth, the 

 Ceratodus has two vomerine teeth in the upper part of the mouth. 

 These are simple convex, long laminaj, with serratures on the 

 outer edge. They are inserted obliquely to the vomerine axis, 

 and are placed at right angles to each other. The teeth of 

 the Ceratodus have an herbivorous type, while those of the 

 Lepidosiren are more adapted for cutting and piercing, and there- 

 fore are carnivorous. The intestines of the Earramanda are filled 

 with partially decayed vegetables. 



It is worthy of note that the nature of the habitats of the fossil 

 fish exactly corresponds with that of the recent.' They lived in 

 dismal, muddy flats, and buried themselves in lumps of clay, 

 and, using their lungs, breathed through a hole purposely made 

 for communication with the surrounding atmosphere. When 

 these blocks are broken, the interior shows beautiful casts of the 

 scales. 



These brief notes show plainly how the natural history of the 

 Rhsetic Ceratodus — at one time so strange and puzzling — is 

 explained by the remarkable discovery of the Queensland Earra- 

 manda. It also corroborates the well-known fact that the 

 Australian fauna have a most distinct Jurassic type. 



The student of TTatural Histcry is invited to visit the unique 

 collection of the remains of the Ceratodus in the Eristol Museum, 

 in which every variety of the fossil teeth from the Aust bone 

 bed may be seen in juxta-position with the recent fish, caught in 

 the Mary river of Queensland. 



