QUADRULA 827 
There has been some dispute as to what name should be 
applied to this species. In 1829 Say fully described in the New 
Harmony Disseminator a species, which he called Unio heros, 
but did not figure. Later in the American Conchology he 
placed it in the synonymy of Unio undulatus Barnes, though 
the figure, which he gives as undulatus in that work and to 
which his description refers, is plainly not Barnes’s species, 
but the heros described in the Disseminator. In 1831 Dr. Lea 
described Say’s species as Unio multiplicatus. Notwithstand- 
ing the fact that Say placed his own species in the synonymy, 
it is perfectly distinct and was properly characterized in his: 
description, and his name will have to take the place of the bet- 
ter known one of Dr. Lea. 
QUADRULA NICKLINIANA (Lea). 
Shell short trapezoid, compressed, solid, inequilateral, beaks 
rather elevated, subcompressed, or slightly inflated, their sculp- 
ture strong, somewhat zigzagged, ridges; anterior end nar- 
rowed and rounded; base line somewhat curved; dorsal out- 
line produced into a wing, which is somewhat obliquely trun- 
cated behind; posterior ridge nearly wanting, feebly and very 
widely double, the lower ridge often being developed into a 
wide lump or swelling about the middle; the whole ending be- 
low ina very wide, faint biangulation at and below the median 
line; surface rudely, concentrically sculptured. The posterior 
end has a few, more or less strongly developed, radial folds 
and besides these there is a set of fine, radial wrinkles reach- 
ing to the front of the posterior ridge. In front of this the 
umbonal region is sculptured with broken corrugations, which 
change into irregular, radial wrinkles and pustules below; epi- 
dermis greenish-brown ; pseudocardinals rough, radial ; laterals 
short, remote: beak cavities very deep and compressed ; mus- 
cle scars large, shallow, the anterior filled with roughened 
nacre; pallial line remote; nacre white, very thick on anterior 
base, suddenly becoming thin behind. 
Length 145, height over all 125, diam. 47 mm. 
Mexico ; Guatemala. 
