. THE NAIADES OF MISSOURI 311 
THE NAIADES OF MISSOURI.—V. 
BY WILLIAM I. UTTERBACK. 
Genus, Strophitus Rafinesque. 
1820—Strophitus Rafinesque, Ann. Gen. Sci. Phys. Brux., p. 316 
1852—Uniopsis Agassiz, Arch. fur Naturg., p. 49. 
(Type, Anodonta undulata Say). 
ANIMAL CHARACTERS:—Branchial opening densely papillose; 
anal papillose or crenulate; mantle connection between anal and 
supra-anal not long and bordered by square, black spots; inner 
gills larger, inner laminae free from, or united to, the visceral 
mass; palpi united antero-dorsal for most of their length; color 
of soft parts variable but with the tendency to have certain parts 
(such as foot, adductors, mantle edge at branchial opening) orange 
in color; marsupium peculiar, consisting of ovisacs divided into 
many compartments at right angles to the laminae; conglutinates 
short, solid cords, (termed placentulae by Ortmann.) 
a SHELL CHARACTERS:—Shell, subrhomboid to subelliptical, 
subsolid, inflated, with low post-tumbonal ridge; disk smooth; 
beaks rather full, sculptured with rather heavy concentric bars 
upeurved behind; epidermis rayed or rayless, polished; hinge 
teeth mere rudiments, sometimes entirely absent. 
Because of the great specialization in marsupial structure, 
the tendency of the inner lamina of the inner gill to become con- 
nected to the visceral mass and also because of a more developed 
hinge, this genus is the highest of the Anodontinae. It is represented 
in this State only by S. edentulus. 
Strophitus edentulus (Say.) 
” ce 
(““Squaw-Foot, Creeper.’’) 
Pl. XXIV, Figs. 80 A—D. 
1820—Alasmodonta edentula Say, New Harm Diss., II, No. 22, p. 340. 
1888——A nodonta shafferiana B. W. Wright, Check List. 
1900b—Strophitus edentulus (Say) Simpson, U. S. Proc. Nat. Mus., 
XXII, pp. 616-618. 
ANIMAL CHARACTERS. 
Nutritive Structures:—Branchial opening doubly papil- 
lose; anal with inner edge crenulated, supra-anal moderately - 
