386 TESTACEOUS MOLLUSCA. 
arched and rising at either end; dorsal edge subrectilinear, rising 
eradually but decidedly from behind; anterior side very broad, the 
wing much elevated ; posterior side narrow: no conspicuous umbonal 
ridge; umbones oblique, not much projecting; lgament narrow ; 
nacre silvery, with a pinkish tinge, especially in front; teeth pro- 
duced, laminar, lateral. 13...2. Bugis, Celebes. The umbones are 
a little eroded in the only example known to me. It is, probably, 
identical with the U. superbus of Lea (Am. Ph. Tr. 9, pl. 42, f. 11), 
yet his description does not exactly apply. 
Unto corsts (t. 23, f. 43), Benson, MS. Oval, inequilateral, rather 
thin, subventricose, concentrically zoned with bluish green and ochra- 
ceous-yellow, rather glossy, smooth, except at the umbones, which 
are adorned with longitudinally divergent slender corrugations, the 
hinder lines of which incline anteriorwards, the front ones posterior- 
wards; a few similar wrinkles radiate subtransversely thence to the 
dorsal end of the concave anterior slope; ventral edge convex; front 
dorsal edge straightish, a little elevated; extremities rounded, the 
front one rather broad; nacre silvery; umbonal cavity ample; teeth 
laminar, compressed. 3...1,4. Assam. Described from a single 
valve. 
Unto ammnus (t. 24, f. 9), Lea, Trans. Am. Phil. Soe. t. 10, f. 12 ; 
on U. 3, p. 88. Oblong or oblong-elliptical, very inequilateral, not 
very thick, rather compressed, rounded at both ends, ochraceous- 
yellow with numerous dark green rays, that are linear or obsolete 
behind, and broader in front, nearly smooth; ventral edge retuse in 
the middle; no umbonal ridge; umbones oblique, eroded, not elevated 
above the dorsal line; inside white, iridescent; cardinal teeth solid. 
1...2%. Tennessee. 
B. (Margaritana = Alasmodonta). No lateral teeth (p. 210). 
Unio Curreyranus (t. 24, f. 10)—Marearirana C. Lea, Trans. 
Am. Phil. Soc. 8, t. 18, f. 40; on U. 3, p. 61. Small, transversely 
oblong subtrigonal, peaked or subrostrated in front, bluntly rounded 
behind, subinequilateral, solid, somewhat compressed, with a yellowish 
brown cuticle, not variegated, concentrically wrinkled, with 2 or 3 
enormous tubercular undulations on the umbonal region, from which 
radiate two blunt umbonal ridges (the dorsal one projecting more 
outwards), the area between which is retuse, and the margin behind 
each of which is indented; ligamental edge not much sloping; liga- 
ment short; inside white, reddish salmon-coloured, or purplish 
liver-coloured ; cardinal teeth strong, no lateral ones. 
2 1 
la al “ay eee Bie 
Tennessee, 
