FLOUNDERS OF GENUS PARALICHTHYS ANB RELATED GENERA 



273 



7. 40 





30 

 20 

 10 



a 



12 13 14 



NUMBER OF (ilLL KAKKKS 



15 



16 



17 



18 



FiGiRE 1. — Frequpney distrilmtinn by miiubor of ;;ill rakers on lower liuili of outer frill arch of three common east -coast 

 species of I'aralichthi/s. Number of specimens: 115 cleiitdtiis, IK! Utlwstiymu, 93 tilhiijiittii. 



gill arch its triangular outline may be readily 

 traced, but often it is very faint. In this study the 

 uppermost gill raker was arbitrarily included when 

 it projected sufficiently above the surface of the 

 gill arch so that it could be manipulated with a 

 dissecting needle. When it was adherent to the 

 arch even though its outline was evident it was not 

 included in the count. It may also be stated that 

 such specimens are comparatively few, and any 

 slight differences in counts which may be made 

 by different observers would have little effect on 

 the final result when large numbers are studied. 

 In this study all the counts were made by me. The 

 counts of gill rakers as here recorded were all made 

 on the blind side because of greater convenience in 



counting. The two sides sometimes varA' slightly 

 in mniiber; but in the small number of specimens 

 in which counts were made on both sides, as a 

 test, there was no average difference in comparing 

 both sides. The counts were then all made on the 

 blind side for convenience and to insure uni- 

 formity. 



ANAL RAYS 



Xext to the gill rakers the number of anal rays 

 constitutes the most important character for sep- 

 arating the three common east coast species, the 

 intergrading individuals being few. This char- 

 acter is especially valuable in separating alh'xjutta 

 fniiu lioth (fciifiitKx and Itthostiymu. A glance at 



980335° 



-52 2 



