NODUI,ARIA 963 
any inflation, 58 mm. long, at the beaks and at the wing 28 
and 20 mm. in diameter; this perhaps is the male form. But 
it is remarkable that in all of the specimens before me, in- 
cluding the possible males, the second (lower) lateral tooth 
of the right valve is wholly or almost wholly wanting. 
Compare with Unio douglasie var. osbeckii Phil., in Heude 
Conch. Fluv. Nank., pl. 65), fig. 1281, which represents the 
Chinese analowae of this form.” 
Var. taiwanica Pilsbry. 
“Shell oblong, narrow, inflated, rather solid, the dorsal and 
ventral margins subparallel, the former slightly arcuate, an- 
terior end rounded, basal margin straightened in the middle, 
posterior end long, somewhat pointed. Beaks full, swollen, 
worn, but showing traces of oblique corrugation on the an- 
terior and posterior slopes, situated at the anterior two-sev- 
enths of the length. Exterior covered with a blackish cuticle, 
somewhat wrinkled along growth-lines. Interior white, iri- 
descent posteriorly. Cardinal teeth compressed, strong, single 
in the right, double in the left valve. Laterals moderately 
strong, rather short. 
Length 49, alt. 25, diam. 19.7 mm.” (Pilsbry). 
Type locality, Formosa. 
Nodularia douwglaske taiwanica Pinsspry, Pr. Ac. Nat. Sci. 
Phila., 1905, p. 750. 
“A mussel closely related to N. dowglasie of China, but 
showing only very weak traces of corrugation.” 
Var. crassidens Haas. 
“Among the typical specimens of N. dowglasie of nearly all 
localities, there occur heavy, inflated shells with extremely 
thick and jagged cardinals and strongly curved laterals, upon 
which I bestow the subspecific name of crassidens. 1 have 
examined specimens from Hainan, from Hunan and from 
Ningpo, Northern China.” (Haas). 
Nodularia douglasie crassidens Haas, Ann. Mag. Nat. Hist., 
(8), VI, 1910, p. 499; Con. Cab., Unio, 1910, p. 75, pl. vit, 
figs. 4, 5. 
