80 Rowland M. Shelley 
Strophitus undulatus (Say 1817) [= 5. rugosus (Swainson) (Dawley 1965)] 
—Fig. 17-18. 
Diagnosis'. Valves without lateral teeth, pseudocardinal teeth vestigial. 
Localities : 14, 17, 19, 21, 26. 
Remarks'. Widespread in small creeks in both the Mississippi and Atlan- 
tic drainages from Canada to Texas, S. undulatus is known only from 
the Tar, Neuse, and Cape Fear systems in North Carolina. Walter 
(1956) found it at four localities in the Piedmont portion of the Neuse, 
and these were later listed by Johnson (1970). In the Tar (Clarke 1983), 
S. undulatus was found alive at five stations, and empty valves were 
encountered at ten. The species is prevalent in the lower reaches of the 
Haw and Deep sub-basins and has not been collected outside of Chat- 
ham County. 
Alasmidonta varicosa (Lamarck 1819) [= A. marginata varicosa 
(Lamarck) (Dawley 1965)] — Fig. 19-20. 
Diagnosis'. Valves without lateral teeth, pseudocardinal teeth prominent; 
posterior slope with radial wrinkles. 
Localities'. 14, 19, 24, 25, 26. 
Remarks'. Alasmidonta varicosa ranges from the St. Lawrence to the 
Savannah river systems. It is comparatively rare south of the Potomac 
(Johnson 1970, Burch 1975, Clarke 1981) and was not encountered in 
the Tar by Clarke (1983). The species was found at five sites in the lower 
reaches of the Haw and Deep sub-basins and is also known from the 
Uwharrie (Yadkin system) and the Catawba rivers in North Carolina. In 
general A. varicosa is rare in Coastal Plain sections and is more com- 
mon in Piedmont habitats and other areas above the Fall Zone. 
Alasmidonta undulata (Say 1817) — Fig. 21. 
Diagnosis’. Valves without lateral teeth, pseudocardinal teeth prominent; 
posterior slope smooth; umbos high and rounded. 
Localities: 11, 19, 25. 
Remarks: Ranging from the St. Lawrence to the Chattahoochee river 
systems, A. undulata is known from the Catawba, Yadkin, Cape Fear, 
Neuse, and Tar systems in North Carolina (Walter 1956; Johnson 1970; 
Clarke 1981, 1983). A fourth locality in the Cape Fear is the vicinity of 
Fayetteville, where Fuller (1977) tentatively reported a juvenile of A. 
triangulata (Lea), an apparent ecomorph that was placed in synonymy 
under A. undulata by Clarke (1981). 
Lasmigona subviridis (Conrad 1835) [= L. charlottensis (Lea) and L. 
decor ata (Lea) (Dawley 1965)] — Fig. 22. 
Diagnosis: Left valve with small interdental projection fitting into 
groove in right valve. 
Locality: 21, N. 
