REPORT ON THE UNIONDAE OF ST. JOSEPH RIVER by 3 
& ‘ 
“®nal Muse 
yposterior adductor muscle scar is as long as it is wide, large, shallow. 
The cavity of the beaks is quite shallow. ‘The pallial line is uni- 
formly impressed. The nacre is white and somewhat iridescent. 
Length 90 Height 50 Diameter 34 
58 30 22 
65 39 27 
78 ; 42 30 
83 44 27 
LAMPSILIS LIGAMENTINA (Lamarck). 
Unio crassus Say, Nich. Encyc., II, 1817, pl. I, fig. 8. 
Mya crassa Eaton, Zool. Text-Book, 1826, p. 217. 
Unio ligamentina Lamarck, Ann. sans Vert. Vol. VI, 1819, p. 72. 
Margarita (Unio) crassus Lea, Syn. 1836, pl. 24. 
Nephronajas ligamentina Ortmann, Ann. Car. Mus., VIII, 1912, p. 325 
Unio ellipticus Barnes, Am. Jl. Sc. VI, 1823, p. 259, pl. XIII, fig. 19. 
Unio carinalus Barnes, Am. Jl. Sc. VI, 1823, p. 259, pl. XI, fig. ro. 
Unio ellipsarius Say, Am. Conch., VI, 1834. 
Unio fasciatus Say, Am. Conch., VI, 1834. 
Unio ligameniinus Lamarck, Anim. sans Vert., Vol. VI. p. 538, 1838. 
Mya gravis Wood, Ind. Test. (Hanley) 1856, p. 199, pl. I, fig. 6. 
Unio luteolus Sowerby, Conch. Icon., XVI, 1867, pl. LVIII, fig. 2392. 
Unio delodontus Sowerby, Conch. Icon., XVI, 1867, pl. LVII, fig. 288. 
Unio crassidens Sowerby, Conch. Icon., XVI, 1868, pl. LXII, fig. 312. 
Unio picius Sowerby, Conch. Icon., 1868, pl. L XII, fig. 313. 
. Unio venustus Sowerby, Conch. Icon., 1868, pl. LXIV, fig. 326. 
Unio upsont Marsh, Conch. Ex. I, 1887, p. 57. 
Unio pinguis Lea, Pr. Acad. Natl. Sci., Phil. I, 1857, p. 84. 
Lampsilis pinguis Simpson, Syn. 1900, p. 540. 
The habitats of this animal are variable. It may be found in- 
differently in sluggish and muddy bayous, living in sand or mud; 
or it may live in the gravel of a swiftly moving stream. These 
differences in environment may account for variableness in form 
and coloration. The nacre is white, varying to bluish and pinkish 
iridescence. The shell is large and much thicker anteriorly than 
posteriorly. ‘he umbones are not prominent. The epidermis is 
yellowish, straw-colored, or light green with numerous dark green 
rays extending from the umbones to the central margin. Old 
specimens are dark reddish brown and show the rays only near the 
umbones. The cardinal teeth are double in both valves; those in 
the right valve are unequal, the anterior being very small, the 
posterior large, triangular and crenulated; in the left valve the 
teeth are more nearly equal, triangular and crenulated. ‘The 
lateral teeth are strong, heavy, elevated and curved towards the 
