PABASOAPHIRHTNOHTJS — WHITE STURGEON 29 



or 11, + 3, 2- or 3-pointed on lower half of arch, the two rows of each arch 

 separated by a broad smooth surface. Dorsal rays 35 to 43, the base of the 

 fin 11.8 to 12.8 in length of head and body; anal rays 20 to 23, ventral 23 to 

 26, pectoral 43 to 49; caudal filament scarcely developed. Dorsal scutes 

 16 to 19, lateral 41 to 47, ventral 10 to 13; spines of dorsal and lateral scutes 

 usually not far from even with their posterior margin; area between dorsal 

 and lateral and between lateral and ventral series of scutes more or less 

 densely covered with small denticulated ossifications, diminishing in size 

 and abundance from above downward; some imperfectly formed plates 

 along base of dorsal row of shields as far forward as the backward reach of 

 the pectorals, these plates becoming more numerous and larger farther 

 back, where they are continuous with those which roof the caudal peduncle; 

 belly wholly naked to front of ventrals ; breast with a few bony points similar 

 to those on the lower part of the sides. 



This species is known to us at present only from the Mis- 

 sissippi River at Grafton and Alton, Illinois. It is rare in. the 

 catches at those places, only one in three hundred of the shovel- 

 nosed sturgeons taken belonging to this species. It is said by 

 Mr. H. L. Ashlock, who first brought the fish to our notice, to 

 be somewhat commoner in the lower Missouri. The spawning 

 season is between June 1 and August 1. The sexual differences 

 are unknown, all our seven specimens being males. The fish 

 is said by Mr. Ashlock to prefer swifter water than the common 

 shovel-nose. The stomachs of the seven types were nearly 

 empty, and the greatly comminuted matter which thejr con- 

 tained was whollv unidentifiable. 



