No. 492] 



POLYODON SPAT HULA 



761 



to back-off when their snouts strike against the net. From such 

 actions one is led to think that if these fish should swim with much 

 force into mud of a very viscid consistency, they would oftentimes 

 be trapped, for from the above observations they appear too stupid 

 to pull back and loose themselves. Since the fish lacks the powder 

 to turn its head from side to side, it cannot stir the mud with its 

 spatulate snout, as Jordan and Evermann claim, but must agitate 

 the silt by a general movement of its entire body. In this process 

 the spatula no doubt plays an important role since it is a consider- 

 able portion of the anterior end of the body. 



The food of Polyodon is cxtrcMnely abmuhint in tlio lakes, ami 

 they grow to be very hir.uv and li('a\ ily proportioned in snch j)laces. 

 One may distinguish almost at a u'lance between a fish that has 

 lived in the lakes and onv from the river; tli<> latter is i>(H>r and 

 slender as compared with the former. The lake-fish contains a 

 much heavier roe, averaging ten or i\velvt> ponnds, whereas riv(>r- 

 fish often have only three or foin- poinids. 



The stomach of Polyodon, in addition to its ciustacc^an diet, 

 contains great numbers of a cestode parasite. Diix^lhriiun ha.sfatum 

 (I.inton). ITiHidreds of these little yeli()\\ -luailed taj)e-worms 

 measuring three or four incli(\s in hMiuili are often j)resent in a 

 single stomach. 



Polyodon hke Lepidostens is fi'e(|iient!y .>een to leap from the 



time, 'i'hey make a vigorons jnmp. nsnally clearing the water 

 entirely, and at times turning over backwards in the air so as to 

 enter the water either head foremost or by striking on their backs. 

 Apparently one fish may .sometimes be seen to jump repeatedly 



The object of snch leap'ing 



