28 JACOB REIGHARD. 



C. The Hogsucker (Catostomus nigricans}. 



v 



42. The hogsucker has been seen to breed in early May on the 

 grounds used by the red-horse. 



43. No difference in the coloration of the sexes has been noted 

 at any season. 



44. The males observed were on the average much smaller 

 than the females. 



45. The anal fins of the male are on the average about 17 per 

 cent, longer than these of females of equal length. The remain- 

 ing fins do not differ greatly from those of the female. 



46. Both sexes are provided with pearl organs which are larger 

 and more widely distributed in males than in females. 



47. Effective pearl organs occur in the males on both surfaces 

 of all the fins, on the upper surface of the head, on the opercle 

 and on every scale of body and head except those of the ventral 

 surface (Fig. 7, lower male). 



48. Pearl organs occur in the female in the same situations as 

 in the male except that they are lacking on the head, sides of 

 body, dorsal fins and lower surfaces of the paired fins. Those of 

 the anal are effective. 



49. Of all the fins the anal of the male exceeds that of the 

 female in length by the largest percentage. It also bears the 

 largest and most effective pearls. 



50. In the field the sexes may be distinguished by difference 

 in average size and by behavior. 



51. The breeding behavior is like that of the white sucker in 

 the particulars enumerated in paragraphs II, 12, 13, 15, 20, 24. 



52. In the hogsucker not less than six nor more than eight 

 males have been seen to "pair" with a single female at one time. 



53. In the spawning position one male lies on each side of the 

 female and others place themselves above these and against the 

 sides and back of the female so as to form a mantle about her, 

 from which her head and tip of her caudal may project (Fig. 7). 



54. The distribution of pearl organs generally over body and 

 fins in both sexes is such that in the spawning position the 

 surfaces of males in contact with females and with other males as 

 well as certain of the surfaces of females in contact with males 

 are more or less roughened and the fish are thereby the better able 

 to maintain their positions. 



