586 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 117 



The tubercle development of males of E. stigmaeum is quite similar 

 to that described above for E.jessiae, exxept that the fin tubercles are 

 better developed (especially in smaller specimens), and there is a 

 puzzling type of geographic variation present. Males of E. stigmaeum 

 from Kansas, Kentucky, and Tennessee (UMMZ, USNM) are very 

 similar to males of E.jessiae in pigmentation, maximum size of males 

 and great development of ventral scale tubercles as contrasted with 

 fin tubercles; however, most males from Alabama and Mississippi 

 (UMMZ) are smaller, have less well-developed pigmentation, and 

 have the fin tubercles well developed and the ventral scale tubercles 

 almost absent. This is contrary to most tuberculate darters, which 

 have tubercles better developed in more southern populations. 

 Further study may show subspecific or specific differentiations. 



Tubercles are present on males of the northern populations of E. 

 stigmaeum from April 6 (UMMZ 165344, Kentucky, E. Fork Barren 

 R.) to April 24 (USNM 163074-5, Kentucky, Green R.). At maxi- 

 mum development (UMMZ 171769, Kansas, Spring R., April 7), 

 ventral scale tubercles start at a point one-third of the distance from 

 the pelvic to the anal fin origin and extend onto three rows of scales 

 per side just anterior to the genital papilla. Tubercles are not present 

 on the scales above the anal fin base or on the ventral surface of the 

 caudal peduncle in any of the males I have examined, but they will 

 probably be found to be present when additional material is examined. 

 One of the three 37 mm. males in this collection shows the best develop- 

 ment of anal fin tubercles; they are present on the second anal spine 

 and on all of the soft rays. Pelvic fin tubercles are developed distally 

 to the fork on the ventral surface of pelvic ray 3 and on the entire 

 length of rays 4 and 5. There seems to be a tendency for the fin 

 tubercles to be best developed in smaller specimens and the ventral 

 scale tubercles to be best developed in larger males. 



In the southern population of E. stigmaeum, fin tubercles but not 

 ventral scale tubercles are present on males from four collections taken 

 from April 2 (UAIMZ 155359, Mississippi, Bogue Chitto R.) to May 4 

 (UMMZ 166388, Alabama, Luxapallila Cr.). A 36 mm. male from 

 UMMZ 155359 has tubercles on the distal three-fourths of all the anal 

 soft rays but none on the spines. A 29 mm. male (UMMZ 163553, 

 Alabama, Big Escambia Cr.) has a few small tubercles on the distal 

 half of the second anal spine. The 36 mm. male has the best devel- 

 oped pelvic fin tubercles on the distal three-fourths of the ventral 

 surface of pelvic soft rays 2-4. Males in one southern collection 

 (USNM 166055, Alabama, Alabama Dr., April 6) have poorly developed 

 pelvic fin tubercles, lack anal fin tubercles, and have ventral scale 

 tubercles starting one-third of the v/ay posteriorly from the pelvic to 

 the anal fin origin and extending onto 3 rows of scales just anterior to 



