REPORT ON THE UNIONDAE OF ST. JOSEPH RIVER 5 
Length 50 Height 23 Diameter 10 
83 42 : 28 
93 44 26 
165 70 45 
175 75 48 
LAMPSILIS IRIs (Lea). 
Unio iris Lea, Tr. Am. Phil. Soc., III, 1830, p. 439, pl. XI, fig. 18. 
Lampsilis iris Baker, Moll. Chi., Pt. I, 1898, p. 105, pl. STI, fig: Fy XIV 20. 
Eurynia (Micromya) iris Ortmann, Ann. Car. Mus., VIII, 1912, p. 341, fig. 
DiS. i 
Unio cone Lea, Tr. Am. Phil. Soc., VI, 1838, p. 33, pl. X, fig. 28. 
Unio novi-eboraci Lea, Tr. Am. Phil. Soc., VI, 1838, p. 104, pl. XXIV, fig. 114. 
Unio cresserus Hanley, Test. Moll., 1842, p. 196. 
Unio radiatus DeKay, Zool. N. Y., Pt. 5, 1843, p. 189, pl. XVII, fig. 236. 
Unio subrostratus Kuster, Conch. Cab. Unio., 1861, p. 203, pl. LX VII, fig 
But two specimens of this shell are,available for description, and 
both are evidently quite young. The shells are characterized by 
the beautiful silvery white nacre which, posteriorly, becomes 
iridescent, the short erect teeth, the interrupted bands of green, 
and the foldings on the beaks. In outline, the shell is elliptically 
oval, thin, small and transversely compressed. The lines of growth 
are widely separated but conspicuous. The cardinal teeth are 
triangular, small and erect. They are double in the left valve and 
single in the right. The lateral teeth are long, thin straight and 
not much elevated. ‘he anterior adductor muscle scar is deeply 
impressed; the posterior is slightly impressed and very iridescent. 
The pallial line is quite faint. The cavity of the shell is small and 
narrow; of the beaks, shallow and triangular. 
Length 50 Height 26 Diameter 14 
a7, 19 rg 
LAMPSILIS ALATA (Say). 
Unio alatus Say, Nich. Encyc., II. 1817, pl. IV. fig. 2. 
Lampstlis alatus Baker, Moll. Chi., Pt. I, 1898, p. 97, pl. XVIII. 
Unio alata Lamarck, An. sans Vert., VI, 1819, p. 76. 
Mya alata Eaton, Zool. Text-Book, 1826, p. 219. 
Symphynoia alaia Lea, Tr. Am. Phil. Soc., III, 1830, p. 448. 
Lymnadia alata Swainson, Treat. on Mal., 1840, p. 256, fig. 48. 
Mysca alata Swainson, Exotic Conch., 2nd. ed., 1841, p. 28, pl. VII. 
Metaptera alata Stimptson, Shells of N. Eng., 1851, p. 14. 
Proptera alata Ortmann, Ann. Car. Mus., VIII; 1912, p. 333. 
This is a large, oval shell, rather thin for its size and triangular 
when the alae are present. The umbonal slopes are rounded; 
the alate postero-dorsal margin is quite compressed. The ventral 
