BREEDING TUBERCLES IN FISHES — COLLETTE 575 



Gymnocephalus cernua (USNM, UMMZ; 60-87 mm.) with greatly 

 enlarged testes or on 20 egg-filled females (68-158 mm.) from these 

 and nine other USNM collections. Tubercles are absent from five 

 males of G. schraetser (ANSP, UMAIZ, USNM; 92-117 mm.) with 

 greatly enlarged testes and from nine egg-filled females (105-155 mm.). 

 Smitt (1892, p. 42) reported that there was little external distinction 

 between males and females of Gymnocephalus acerina (Giildenstadt). 

 He found that males had longer pelvic fins and deeper bodies than 

 females, but he did not mention breeding tubercles. The one speci- 

 men available to me (USNM 28564) is an egg-filled female lacking 

 tubercles. 



Genus Percarina Nordmann 



I have examined three specimens of Percarina demidoffi Nordmann 

 (USNM 37308 and MCZ 26527). All are females filled with eggs. 

 All lack tubercles. 



Tribe Etheostomatini 



The darter tribe is the most speciose in the family, with 102 valid 

 described species, plus about a dozen undescribed ones. Bailey {in 

 Bailey, Winn, and Smith, 1954; and in Bailey and Gosline, 1955) has 

 recently reduced the nominal genera of darters to three: Percina 

 (22 species in 8 subgenera), Ammocrypta ( 5 species in two subgenera), 

 and Etheostoma (76 species in 13 subgenera). Several changes within 

 subgenera, based on tubercle patterns, seem necessary, especially 

 in the subgenera Ericosma, Boleosoma, loa, Etheostoma, and Oligo- 

 cephalus. I hesitate to make nomenclatorial changes based primarily 

 on breeding tubercle patterns, and in this paper I shall merely discuss 

 some of the groups in which reallocation seems desirable. 



Genus Percina 



Subgenus Hypohomus Cope 



This subgenus contains three species: aurantiaca (Cope), cyma- 

 totaenia (Gilbert and Meek), and one undescribed species. Males 

 apparently lack breedmg tubercles, although a unique adaptation 

 probably performs the same function. Bailey (1948) pointed out 

 that males of Hypohomus have a thin flangelike midventral keel on 

 the lower edge of the caudal peduncle near the caudal base bearing 

 strongly developed ctenoid scales. This seems especially significant, 

 because males of the subgenus Hypohomus have the fewest enlarged 

 midventral scales of any of the subgenera of Percina. It will be 

 interesting to see how these keels function in spawning. 



