90 U.S. NATIONAL MUSEUM BULLETIN 259 



from Lower Ordovician rocks and flowing into the nearby St. Francis 

 River. 



Distribution and ecology. — This species is known only from a 

 seep and a small stream; the latter presumably being fed directly by 

 ground-water resurgence. The two localities are separated by about 

 25 miles, but both occur in lower Paleozoic sedimentary rocks situated 

 just east of the St. Francis River. The collection from the type 

 locality (April 1938) contained three ovigerous females with the 

 following lengths and numbers of eggs or embryos: 6.75 mm (9 em- 

 bryos), 6.75 mm (4 embryos), 8.25 mm (7 eggs). 



Remarks. — Hubricht and Mackin (1940) called attention to the 

 laterally spined telson of specimens from eastern Missouri, but they 

 apparently did not consider this material specifically distinct from 

 S. americana (=S. alahamensis s. str.). My examination of the 

 above collections revealed not only major differences in the structure 

 of the telson but a number of other diagnostic characters as well. 



It is a real pleasure to name this species after Dr. Thomas C. Barr, 

 Jr., who has probably done more than any other individual to further 

 the study of biospeleology in North America and who has assisted 

 in collecting many subterranean amphipods. 



Stygonectes balconis Hubricht 



Stygonedes flagellatus (Benedict). — Uhlenhuth, 1921, pp. 96-98 (in part?). 



Stygonectes balconis Hubricht, 1943, pp. 706-707, pi. 8 (in part) [Type locality: 

 Boyetts Cave, 14 miles NW of San Marcos, Hays Co., Tex.].— Barnard, 

 1958, p. 74.— Hubricht, 1959, p. 878.— Nicholas, 1960, p. 129 (in part).— 

 Reddell, 1965, p. 160 (in part) .— Holsinger, 1966, pp. 113-116, figs. 64-73 

 (in part). 



Material examined 



Texas. — Hays Co.: Boyetts Cave, 2 males and 2 female syntypes (USNM 

 79323), J. Mackin, Aug. 26, 1939; 6 male topotypes, J. Mackin, Aug. 26, 1948 

 (LH) ; 4 males topotypes, J. Reddell and W. Russell, Mar. 30, 1963 (JRH) ; Travis 

 Co.: Irelands Cave, 1 male, W. Russell, Mar. 14, 1964 (JRH). 



Diagnosis. — A relatively large troglobitic species closely allied 

 morphologically with S. alahamensis but differing from the latter 

 by having a few more spine teeth on gnathopodal propod palmar 

 margins, few more marginal setae on coxal plates of pereopods 2-4 

 and posterior margins of abdominal side plates, approximately 2 

 more spines on uropods 1 and 2, and up to 3 additional spines on 

 apex of telson in males. Further distinguished by possessing only 

 simple lateral sternal gills and by the absence of median sternal and 

 pleonite sternal gills. Largest males, 16.00 mm; largest females, 

 9.75 mm (12.50 mm?). 



