to 
THE AMERICAN MIDLAND NATURALIST 
from twenty to thirty-five or more bright green rays. In some 
specimens the rays do not persist in the posterior portion; when 
present in old specimens they become wide,—about eight milli- 
meters; or there will be an alternation of a wide ray with a narrow 
one. The ligament is rather stout, short and wide and of a dark 
chestnut color. The cardinal teeth are double in the left valve and 
single in the right. The posterior muscle scar is rounded, as wide 
as long and not much impressed. .The protractor pedis muscle 
scar is wider than long, deeply impressed anteriorly and coarsely 
striated. The pallial line is deeply impressed anteriorly but only 
slightly impressed “posteriorly. The cavity of the beaks is deep. 
The nacre is silvery white with little or no iridescence; sometimes 
pink. ; 
Length 125 Height 100 Diameter 60 
100 65 36 
118 84 - 52 
126 88 54 
LAMPSILIS LUTEOLA (Lamarck). 
Unio luteola Lamarck, An. sans Vert., VI, 1819, p.-79 ie 
Lampsilis luteolus Baker, Moll. Chi., Pt. I, r898, p. 103, pl. XI, XXXVI 
figeer2 
Unio infiaius Barnes, Am. Jl. Sci., VI, 1823, p. 266. 
Mya inflata Eaton, Zool. Text-Book, 1826, p. 221. 
Unio siliquoideus Barnes, Am. Jl. Sci., VI, 1823, p. 269, pl. XIII, fig. 150. 
Unio childreni Hanley, Biv. Shells. 1843, p. 193, pl. XXIII, fig. 57. 
Unio hydianus Kuster, part. Conch. Cab. Unio, 1861, p. 201, pl. L XVII fig. 1. 
Unio distans Anthony, Am. J]. Conch., I, 1865, p. 156, pl. XIII, fig. 2. 
Unio multiradiatus Sowerby, Conch. Icon., XVI, 1868, pl. LXI, fig. 306. 
Unio affinis Sowerby, Conch. Icon., XVI, 1868, pl. LXI, fig. 307. 
This form, quite abundant in the St. Joseph River, is variable 
in outline,—a fact that probably gave rise to the extensive 
synonymy that has been established on this shell. The shell is 
large, elongated and rather thin. It is rounded anteriorly and 
somewhat pointed posteriorly. ‘The epidermis is a light horn color, 
often shading into brown on.the posterior slope. There are many 
bright green, narrow rays, departing from the beaks and covering 
nearly three-fourths of the disk. The umbones are prominent, 
slightly elevated, of a brown or green color, usually eroded, and 
marked by fine undulating ridges. The ligament is stout, short 
and wide, and of a dark chestnut color. The cardinal teeth are 
double in both valves. The anterior adductor muscle scar is 
excavated, longer than wide, large and coarsely striated. The 
