920 QUADRULA 
quite strongly from all the Chinese species figured by Heude; 
especially in that the teeth are not so oblique as in the related 
forms, such as plumbeus Chemn., polystictus and fibrosus 
Heude. The striation of the lateral teeth like Castalia I find 
likewise, sometimes stronger, but varying in individual speci- 
mens, both in the above named species and in Heude’s figures. 
It is remarkable that in all the species collected by Fruhstorfer 
in Tonkin, the silky lustre, which is found in so many of the 
Chinese species, is absent.” 
QUADRULA NODULOSA (Wood). 
Shell subtriangular, inflated, solid, beaks full and high, ter- 
minal or subterminal ; posterior ridge full, subangular, ending 
at the posterior base of the shell in a rounded point; anterior 
end cut away and rounded below ; base line somewhat curved ; 
outline of dorsal slope a long, almost even, curve; surface 
somewhat concentrically ridged and covered with coarse nod- 
ules; posterior end with very strong, curved, subnodulous 
ridges, which are often divaricate on the posterior ridge; epi- 
dermis rough, tawny-brown; hinge plate very wide; pseudo- 
cardinals radial, curved, rough and split, laterals with strong, 
vertical striz ; anterior muscle scars small, deep; beak cavities 
very deep, compressed; nacre straw-colored, thinner and iri- 
descent behind. 
Length 90, height 69, diam. 45 mm. 
China. 
Mya nodulosa Woop (in part), Gen. Conch. 1, 1815, p. 106, 
pl. xxi1, figs. 1, 2;..Jndex, Test, 1825, ip. 42, plein he. aon. 
Index West) Rev... 1856ip:.10) play eso: 
OQuadrula nodulosa StMPSON, Syn., 1900, p. 708. 
Unio nodulosus SowrerRBy, Conch. Icon., X VI, 1868, pl. LXxX XIII, 
hg. 430. 
Margarita (Unio) nodulosus Lea, Syn., 1836, p. 16; 1838, p. 
TS. 
Margaren (Prisodon) nodulosus Lea, Syn., 1852, p. 27: 1870, 
p27 
