214 MUSCHELKALK, LIAS, AND OOLITE. 



zoological characters to the Carboniferous order, than to the- 

 calcareous formations which are superior to the New red 

 sandstone. This conclusion accords with that which M- 

 Agassiz has drawn from the character of its fossil Fishes. 



Fishes of the Muschelkalk, Lias, and Oolite Formations. 



The Fishes of the Muschelkalk are either peculiar to it. 

 or similar to those of the Lias and Oolite. The figure en- 

 graved at PI. 27% is selected as an example of the charac- 

 ter of a family of Fishes most abundant in the Jurassic or 

 Oolite formation ; it represents the genus Microdon in the 

 family of Pycnodonts, or thick-toothed Fishes, which pre- 

 vailed extensively during the middle ages of Geological His- 

 tory. Of this extinct family there are five genera. Their 

 leading character consists in a peculiar armature of all 

 parts of the mouth with a pavement of thick round and flat 

 teeth, the remains of which, under the name of Bufonites, 

 occur most abundantly throughout the Oolite formation.* 

 The use of this pecuUar apparatus was to crush small shells^ 

 and small Crustacea, and to comminute putrescent sea- 

 weeds. The habits of the family of Pycnodonts appear 

 to have been omnivorous, and their power of progression 

 slow.f 



Another family of these singular Fishes of the ancient 

 world, which was exceedingly abundant in the Oolitic or 

 Jurassic series, is that of the Lepidoids, a family still more 



* PI. 27c. Fig-. 3. represents a five-fold series of these teeth on the palate 

 of Pycnodus trigonus from Stonesfield ; and Fig-. 2, a series of similar teeth 

 placed on the vomer in the palate of the Gyrodus Umbilieus from the great 

 Oolite of Durrhcim, in Baden. 



■j- A similar apparatus occurs in a living family of the Order Cycloids, in 

 the case of tiie modern omnivorous Sea Wolf, Anarrhicas Lupus, and other 

 recent Fishes of different families. M. Agassiz observes, that it is a common 

 fact, in the class of Fishes, to find nearly all the modifications which the 

 teeth of these animals present, recurring in several families, which in other 

 respects are very different. 



