No. 645] 



VERTEBR.^ OF FISHES 



365 



The portion of the vertebral column affected is the caudal, 

 not the precaudal (abdominal) division: the averages for 

 the precaudal vertebrae are 22.82 (+0.02) for 1919,, and 

 22.85 (+ 0.01) for 1919, for the caudal vertebrae, 18.60 

 (+ 0.035) for 19198, and 18.87 (+ 0.01) for 1919^. Simi- 

 larly, the number of scales in the lateral line averages 

 higher in the 19199 lot : the modal number is 40 rather than 

 39 as it is in 1919^ class; the average number is 40.05 

 (+ 0.04) rather than 39.65 (+ 0.04). The modal numl)er 



