6 



BULLETIN 214, UNITED STATES NATIONAL MUSEUM 



Table 1. — Number of vertebrae recorded from radiographs of genera and species of 



Scaridae — Continued 



I Abdominal vertebrae lack the haemal spine, or a rudiment may occur on the last vertebra; this rudiment 

 does not reach past the next posterior vertebra. 



' The first caudal vertebra is the one on which the haemal spine reaches to or beyond tips of first anal 

 pteryglophores. 



Probable phylogeny of scarid fishes 



It is probable that the labrid and scarid fishes were derived from 

 common ancestral stock, that the scarids separated from that labrid 

 stock very early, and that Cryptotomus represents the most labridlike 

 genus of the scarids living today, because of its labridlike teeth at the 

 front of the jaws. These teeth slant forward and the head is more 

 acutely angled than in other scarids. However, in Cryptotomus the 

 pharyngeal mill is fully developed, placing it with the scarids. Since 

 Cryptotomus and Nicholsina are more labridlike than other scarids 

 and since these two genera have three rows of teeth on each upper 

 pharyngeal bone, it is assumed that three such rows represents the 

 more primitive condition and that any reduction in number of rows 

 represents a more speciafized condition. 



