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University of Washington Publications in Biology [Vol. 2. 



ON 



Fig. 36. A view of the dorsal side of the head of Catostomus syncheilus, showing the 

 fontanelle (dotted) surrounded by ossified bones. Fon — fontanelle. Drawn by Arthur 

 D. VVelander. 



Fig. 37. A view of the ventral side of the head of Pantosteus delphinns, showing the 

 overhanging upper lip and the notches at the corner of the lips where the upper and 

 lower meet. Drawn by Arthur D. Welander. 



'7b. Fontanelle closed in adults and nearly closed in young; at 

 most represented by a narrow slit; scales 14 to 18+80 to 93 

 + 11 to 13; scales before dorsal 37 to 52, usually about 40 to 

 42; anal rays 6 to 7; dorsal rays 10 to 12; eye 6y 2 to 8 in 

 head ; peritoneum dusky ; scales little if any increased in size 

 posteriorly. 



9a. Lower lip deeply incised, so that not more than 1 row of 

 papillae extend across the symphysis. Range : Upper Sac- 

 ramento River and Goose Lake Drainage. Freshwater. 

 Not common. 



70. Catostomus micro ps Rutter 



9b. Lower lip not deeply incised, so that 2 or more rows of 

 papillae extend across the symphysis. Range : Rouge and 

 Klamath rivers, Oregon and California. Freshwater. Com- 



Fine-scaled Klamath River Sucker 



71. Catostomus rimiculus Gilbert and Snyder 



6b. Lower lips very deeply incised, no row of papillae crossing the 

 mid-line or at most only a rudiment of a row ; fontanelle present. 



10a. Fewer than 80 scales along the lateral line. 



