BREEDING TUBERCLES EST FISHES — COLLETTE 



581 



and tend to be confined to the distal portion of the soft rays. Tuber- 

 cles sometimes are developed on the few imbedded breast scales, the 

 modified midveutral scales, many of the scale rows lateral to the 

 midventral rows, and on the ventral rows of caudal peduncle scales. 

 As in P. shumardi and P. evides, small tubercles develop near the pores 



Figure 3. — Male of Percina (Imosloma) uranidea showing the distribution of breeding 

 tubercles (TU 7965, Louisiana, Pearl River, Feb. 16, 50 mm. SL). 



of the infraorbital and preoperculomandibular canals. Small tubercles 

 are present along some of the rays of the ventral half of the caudal 

 fin. A few specimens have tubercles developed on the ventral 2-5 

 rays of the pectoral fin, a condition found only in one other species 

 of the Etheostomatini, Etheostoma (Oligocephalus) spectahile. 



The abundant material of P. uranidea in the Tulane University 

 collections taken throughout the year from Pearl River makes a study 

 of the annual development of the breeding tubercles possible. Maxi- 

 mum development occurs from February 8-16 (table 2), when the 

 peak of spawning most likely occurs. 



Table 2. — Development of breeding tubercles in males of Percina (Imostoma) 

 uranidea from the Pearl River (see table 1 for abbreviations; L. Caud.== lower 

 caudal fin) 



