60 



Pisces — Continued. 



Haplomi 34 



Isospondyli 7^ 



Plectospondyli 150 



Scyphophori 



Nematognathi - ^7 



Notacanthi • • 



Glanencheli 



Ichthyocephali 



Holostomi 



Enclielyccphali 2 



Colocephali 3 



Halecomorphi 2 



Ginylymodi 15 



Glaniostomi 30 



iSelachostomi 1 



Holocephali 2 



Plagiostomi 46 



Dipnoi 



Sit) 



Dermopteri 8 



Leptocaedii 1 



Total species of Vertebrata 2, 249 



This number is considerably below the truth, as many ot the fishes, 

 both of the ocean and of the fresh waters, remain undescribed. 



It is more difficult to state the number of species of the inferior divis- 

 ions of the animal kingdom. It is asserted that 8,000 species of Cole- 

 opterous insects have been discovered in the Nearctic region, and that 

 this is probably about two-thirds of the whole. This would give 12,000 

 species of this the most numerous order, and the Lepidoptem, Hymenop- 

 tera, and Biptera will follow at no great distance. Probably 50,000 is 

 below the mark as an estimate of the number of species of insects of this 

 region. One thousand species are to be added for the remaining Arthro- 

 poda—say, 200 Myriopoda, 400 Arachnida, and 400 Crustacea. Of worms 

 of land and water there are numerous species, the greater proportion 

 of which are not yet known to science. 



The number of the Mollusca and Molluscoida from the coasts and inte- 

 rior of the North American region is about 1,824, of which only 400 are 

 marine. Of the remainder, 1,034 live in the numerous rivers and lakes, 



