No. 446.] ORAL BREATHING VALVES OE TELEOSTS. i6l 



CATOSTOMID^:. 



BB. Papillae not in fold-like rows. 



C. Papillae on proximal half ' of valve 

 CC. PapiUs over whole valve. 



D. Papillae crowded over whole valve ; 



] [ 11 1 t ze of 

 1 rows. Distal papillae 



SILURID^. 



Papillae on both valves. 



B. Thickenings triangular and in Mand. V. 



C. Thickening erect-triangular, (apex toward free edge) 



Amiurus vulgaris 

 CC. Thickening inverted-triangular, apex toward tooth pads. 



D, Pigment on thickening and spreading in a crescent 

 through the valve on either side . Noturus gyrinus 

 DD. No pigment in either valve . . . Noturus miurus 

 BB. Thickening in Max. V. and not triangulai 

 E. Thickenir 



closer set than those on Max. 

 EE. Thickening not a vertical rod. 

 . F. Thickening shaped like a sphere with a rod rum 

 through it parallel to the free edge 



Amiurus natalis (Fig. . 

 FF. Thickening spherical, barely touching attachm 



ng I the wic 



valve. Papilla? .so small 



= Distal, — away from 



