1. P0LY0T1OX. 347 



Tho shovel-like process is about one-fourth of tlie entire length in 

 adult examples, but only two-fifths in young. The opercular flap 

 extends far beyond the pectorals in old examples, and nearly to the 

 ventruls in young. Gill-rakers exceedingly fine and numerous. 

 Upper caudal fulcra narrow, from sixteen to twenty in number. 



Mississippi and tributaries. 



a. Stuifed, 5 feet long. 



h, c, d-e,f-h. Half-grown and young (in spirits). Mississippi. 



2. Polyodon gladius. 



Polyodon gladiiis, Martois, Monafsbcr. Ak. IViss. i?er^. 1801, p. 47G ; 



Diiineril, Nouv. Arch. 3Iiis. iv. p. 105, pi. 22. lig. 2. 

 (Spatularia) augustiiblium, A'i[«y>, irieym. uirch. 18C2, p. 278. 



The shovel-like process is much narrower than the head ; oper- 

 cular flap not extending beyond the pectoral fin. Gill-rakers in 

 moderate number, and distant from one another. Upper caudal 

 fulcra large, six in number. 



Yantsekiang. 



