BREEDING BEHAVIOR OF SUCKERS AND MINNOWS. 27 



not observed at other seasons. It extends forward above the 

 eye. 



32. The backs of certain males show elongated white flecks 

 running lengthwise, but they do not show the red lateral stripe 

 characteristic of the white sucker at the moment of pairing. 



33. The fins of males are longer than those of females of equal 

 length by the following average percentages; lower lobe of caudal 

 33, anal 14.5, pectoral 16, pelvic 9, dorsal 9. 



34. The lower lobe of the caudal of the male is about 14 per 

 cent, longer than the upper lobe. 



35. Effective pearl organs occur in the males on all the scales 

 of the back and sides; on both surfaces of caudal, anal, pelvic 

 and dorsal; on the upper surface of the pectoral and on the sides 

 and top of the head to the end of the snout (Fig. 5). 



36. Minute non-effective pearl organs occur occasionally in 

 females on the top of the head and on the first few scales of the 

 back behind the head. 



37. Of all the fins of the male, the caudal and anal, which 

 exceed the corresponding fins of the female in length by the 

 largest percentage, bear the largest and most effective pearls. 



38. The males may be distinguished from the females on the 

 breeding grounds by the pearl organs, by length of anal fin, by 

 behavior and in some cases by differences in coloration (white 

 flecks on the back). 



39. The behavior of the fish on the breeding grounds is like 

 that of the white sucker in the particulars stated in paragraphs 

 II," 12, 13, 14 (except color change), 15, 16, 17, 18, 19, 20, 21, 



22, 24, 27, 28. 



40. The attitude of the pairing males during spawning differs 

 from that of the white sucker (par. 18) in that the backs are 

 more arched and the snouts with their covering of pearl organs 

 are pressed against the sides of the head of the female (Figs. 

 4 and 5). 



41. In the position indicated in paragraph 40 the female is 

 held not only between the tails, caudals and anals of the two 

 males but between their heads as well. 



