APPENDIX. 381 
A. A. Symphonote Uniones proper (p. 174). 
Unio DELPHINUS (t. 20, f. 44), Gruner, Wieg. Arc. 1841, t. 11, f. 1. 
—Del. t. 19, f. 3.— Lea, Am. Ph. Tr. 8, t.17; on U. 3, p. 56. 
Klongated, with an acutangular fin-like projection of the anterior 
dorsal outline; very inequilateral, rather thin (the wing extremely 
fragile), compressed, dark brown, nearly smooth; ventral edge con- 
vex, curving obliquely upwards behind ; hinder dorsal edge rectilinear, 
usually angulated at the extremity; front extremity subtruncated- 
cuneiform ; umbonal ridge rendered subangular above by the con- 
cavity of the anterior slope; nacre iridescent, silvery white; car- 
dinal teeth small, crenulated; lateral teeth very long and straight, 
2 (nearly 4 with the fin)...5. Malacca. 
Unio DELPHINULUS (t. 23, f. 60), Morelet, Test. Novis. 1, p. 31. 
Klongated-oblong, with a shortish fin-like dorsal wing, inequilateral, 
very thin, compressed, smooth, olivaceous-yellow or pistachio-green, 
with a few radiating darker lines on the vicinity of the beaks; ventral 
edge curving upwards behind; wing quite as broad as high, arcuated 
in front, curved behind ; anterior slope concave ; anterior extremity 
briefly sublinguiform ; posterior dorsal corner angular, disposed to 
alation; umbones flat; beaks not raised; nacre silvery; teeth 
laminar, the lateral ones transversely striated. 1), (with the fin 14) 
..24. Yueatan. 
‘ 
A. B. * to *** Non-symphonote nodulous spinous or plicated 
Uniones proper. 
Unio InTERMEDIUsS (t. 20, f. 28), Conrad, Mon. U. t. 35, f. 2. 
Transversely subquadrate, very inequilateral, thick, at most subven- 
tricose, ochraceous- yellow, speckled all over with most crowded 
minute angular dark green markings, a few of which (on the posterior 
side) ave larger than the rest; larger anterior moiety nodulous, pos- 
terior half smooth or with very indistinct incremental plice ; nodules 
divergent and linear on the anterior slope, elsewhere tear-shaped ; 
umbonal ridge preceded by a shallow groove, whose extremity is in- 
dented: ventral edge arcuated; posterior side very short, rounded 
both above and below; umbones a little prominent, eroded, when 
young with 2 or 8 anterior pliciform waves; nacre white or flesh- 
coloured ; teeth solid, the lateral ones rectilinear. 12...2. N. Caro- 
lina. 
Unio sEMIGRANOSUs (t. 20, f. 383), Von dem Busch in Phil. N. C.1, 
p. 19, U. t.1, f. 1, 2,3.  Transversely ovate, inequilateral, solid, 
ventricose, pitch-brown, not rayed, finely and most closely granu- 
lated in the umbonal region, elsewhere smooth; ventral edge more 
