40 



requesting an exchange of lingual ribbons of the Marine 

 Mollusca ; also in Protozoa or Diatomacea. The letter 

 was referred to Rev. E. C. Bolles. 



THE NEW AUSTRALIAN FISH. 



MR. F. "W. PUTNAM gave an account of the interesting 

 and very important discovery of a fish, by Hon. Wm. 

 Forster, in the fresh waters of Australia, that seemed to 

 combine characters of the Ganoids with those of Chime- 

 roids, which were an order of the subclass to which the 

 sharks belonged. This fish has been referred by Mr. 

 Krefft, on account of the resemblance of the teeth, to the 

 genus Ceratodus, known only from teeth found in the 

 Devonian period, and Dr. Giinther, who has lately made 

 an examination of specimens, confirms Mr. Krefft's opin- 

 ion, and is also led from its peculiar structure to unite the 

 subclasses of Ganoids, Dipnoi and Selachians together as 

 one subclass, which he calls Palseichthyes. 



Mr. Putnam thought that, while we only knew the fossil 

 Ceratodus from its teeth, it was venturing too far to refer 

 the Australian fish to the same genus, especially as the 

 fossil teeth have characters that have heretofore associated 

 the genus more intimately with sharks than with Ga- 

 noids ; and as we are apt to be misled by any single char- 

 acter, teeth being by no means an exception. 



In relation to the new classification proposed by Dr. 

 Giinther, Mr. Putnam, while agreeing with him in uniting 

 the Ganoids with the Dipnoi, as both Mr. Gill and him- 

 self * had previously done, and while admitting that the 

 Chimeroids have affinities with them, was yet doubt- 

 ful about placing the Selachians in the same subclass 

 without uniting the Marsipobranchiates with them, for 



*In a review of the classification of the Vertebrates, in " Huxley's Classification 

 of Animals." American Naturalist, Vol. 3, p. 610. 



