44 -S". W. WILLISTON 



much value as those between any other two groups of reptiles 

 properly called orders. 



That the classification of the vertebrates will some time reach 

 a fairly satisfactory stability is certain, but that this much-wished- 

 for consummation is not at the present time a reality is painfully 

 evident. Especially is the lack of a taxonomic equilibrium 

 between the various groups of reptiles and those of the birds 

 very apparent. In every group of organisms, where individuals 

 and species are abundant, there is a constant, an almost unchecked, 

 tendency to raise the lower divisions to a higher rank, without 

 due regard to their relative values, so far as those of other 

 groups are concerned; and this tendency will never be dis- 

 couraged save by the general morphologist ; the specialist usually 

 lacks that breadth of view so necessary for a proper perspective. 

 The ornithologists, especially, have been in the past a law unto 

 themselves in this respect, without due fear of the results of their 

 taxonomic misdeeds before their eyes. Twenty-five or thirty 

 groups of birds have been given ordinal rank, while it seems 

 evident that the whole class scarcely presents as many or as wide 

 internal differences, unless it be in a few forms, as are found in 

 not a few single groups of reptiles that are usually called orders. 

 But, I respectfully submit, the raising of the orders of reptiles 

 to subclass rank, as Gadow has done, is not the proper solution 

 of this difificulty. Unless we invent superclasses and super- 

 kingdoms, or some entirely new classificatory denominations, an 

 impassable wall will soon be reached, when all the orders are 

 leveled up to subclasses, and we are no nearer a final symmetri- 

 cal classification than we were, though there may have been 

 many excellent opportunities for coining new names. 



The relationship of the mosasaurs to certain modern lizards, 

 the Varanidae, was pointed out by Cuvier in his original descrip- 

 tion of the famous Maestrichtian example one hundred years 

 ago. Goldfuss, Owen, and Marsh all recognized this rela- 

 tionship as a real one, and refused to give to these animals 

 the rank which Cope insisted upon giving. It was Baur, how- 

 ever, who first strongly emphasized the importance of their 

 varanid afifinities. He gave to the mosasaurs only a family rank 



