UNIO 622 
rior end of the laterals: epidermis dark, sometimes dull and 
black. 
Length 35, height 20, diam. 13.5 mi. 
Length 57, height 28, diam. 20 mm. 
Type locality, Lake Diaz, Volusia Co., Fla. Also Lake 
Beresford; Lake Ashby, Florida. 
Umo diazersis S. H. Wricut, Naut., XI, 1897, p. 5. 
Unio coruscus var. fryanus (part), Stmeson, Syn., I1goo, p. 
714. 
This varies insensibly into var. fryanus and to the ordinary 
manifestation, though some of the specimens are remarkably 
different from typical coruscus. 
UNIO TENUISCULUS Frierson. 
“Shell transversely elliptical, rather solid, quite small, being 
the smallest member of the great buckleyi group yet published ; 
smooth, eradiate (except when quite young), brown-olive, 
shining on the sides, the posterior area rough and dull; dorsal 
and basal margins nearly parallel (the former a little arched 
in some examples}. Posterior point low and widely biangu- 
late; truncate in front. Nacre purple and salmon-colored. 
Teeth double in left, single in right valve, quite stout. 
Length 36.5, alt. 20, diam. 14.5 mm.” (Frierson). 
Type locality, Reedy ake, Polk: Co., Fla. 
Unio tenuisculus Frierson, Naut., XXV, IgII, p. 29, pl. 1, 
figs. 4) 56. 
“The shell is differentiated from U. coruscus by being small- 
er; by its parallel outline; by its posterior point being lower 
and biangulate. In proportion to size, it is heavier in texture, 
and when perfect shells of both are compared, it is not so 
shining as is coruscus. The squarely built anterior end is a 
character common to a number of Florida Uniones.” 
Unio Ferrissit Marsh. 
Shell nearly elliptical, solid, convex, inequilateral; dorsal 
and ventral lines rounded; anterior end subtruncated; dorsal 
slope obliquely truncated, meeting the dorsal line at a low 
