REPORT ON THE UNIONDAE OF ST. JOSEPH RIVER II 
QUADRULA RUBIGINOSA (Lea). 
Unio rubiginosus Lea, Tr. Am. Phil. Soc., III, 1829, p. 427, pl. VIII, fig, 10. 
Quadrula rubtginosa Baker, Moll. Chi., Pt., I, 1898, p. 77, pl. XIX, fig. 2; 
> DS ran 
Fusconaja rubiginosa Ortmann, Ann. Car. Mus., Vi tO12;, p 240, Mestas 
a 
ad fates Conrad, Monog. m. IX, 1837, p. 74, pl. XULI, fig. 2. 
Unio trigonus Sowerby, Conch. Icon., XVI, 1868, pl. LXIV, p. 322. 
There are five specimens of this shell in the collection at my 
disposal. ‘he measurements vary considerably from those given 
for the species by Call and Baker, showing that these shells are 
smaller. The shell is quadrate in outline and of moderate thickness. 
There is lateral compression and striation. The epidermis is brown 
or olive green,—some young specimens have rays in the umbonal 
region. ‘The lines of growth are numerous and raised into ridges. 
The anterior margin is round; the posterior margin is curved, 
the ventral margin is emarginate. The umbones are small and 
slightly raised. The ligament is dark brown in color, thick, and 
short. The cardinal teeth are double in the left and single in the 
right valve. The lateral teeth are long, thin and plate-like. ‘The 
pallial line is well marked; in some specimens, it is nearly oblitera- 
ted towards the posterior end. The nacre is pure white to salmon 
colored. ‘There is considerable variation within the species, es- 
pecially in the shape of the posterior portion, and in its corpulency. 
This shell may be distinguished from Quadrula coccinea, which 
it resembles most closely} by its more angular posterior slope and 
its stouter and diverging cardinal teeth. 
Length 90 Height 64 Diamater 33 
88 61 32 
i 2 17 12 
ait 50 33 
QuUADRULA CoccInEA (Conrad). 
Unio coccineus Conrad, Monog., III, 1836, p. 29, pl. XIII, fig. 1. 
Quadrula coccinea Baker, Moll. Chi., Pt. 1, 1898, p 79, pl. SV ees: 
EXCITE Be 
Pleurobema coccineum Ortmann, Anny Care Miss VEL rom. p-.263) 
Unio rubens Menke, Syn., Meth. Moll., 1828, p. 90. 
Unio catillus Conrad, Monog., III, 1836, p> 30, pl. XIII, fig. 2. 
Unio gouldianus Ward, Jay’s Catalog, 3rd. ed. 1839, P. 24. 
Unio cuneus Call, Tr. Ac. Sci. St. Louis, VII, p. 14. 
This is an exceedingly variable species and one of the most 
difficult to diagnose. Its nearest relative is Q. solida. It may be 
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