NECTURITS MACULATtJS. 



427 



have given a definite number of teeth for each dentigerous bone, and Cope ('89) has even 

 employed the nvimber of teeth as a diagnostic between species, but as a matter of fact the 

 number is quite inconstant, and it seems probable that the rows are added to upon their 

 outer or posterior ends as the animals become older. The result of a series of enumera- 

 tions of different specimens may be given in the following tables. 



Table A. 

 Teeth enumeraterl in entire siieeimens. 



Tahle B. 

 Teeth counted in isolated bone.s. 



' These small bones were unfortunately lost in this specimen. 



'The specimeiLs which furnished these isolated bones were generally larger than those used for Table A, whieli 

 accounts for the greater number of teeth. 



^In this average are included the statistics from both tables. 



