121 
1659 Ancylus rivularis Say. 
Shell delicate, moderately elevated; sides slightly convex, 
diverging anteriorly; posterior and dextral slopes concave, ai- 
terior slope convex, and sinistral one nearly rectilinear; apex 
subacute, projecting, 1-3d of the shell posterior to it. Color light 
brown; nacre, in large individuals, white. Lon. 5, lat. 3.5, elev. 
2mm. 
Delaware and Susquehanna rivers.—Montana (Squyer). 
1660 Anodonta ovata Lea. 
1661 Anodonta plana Lea. 
Squyer records these two from Montana. 
1662 Doridium Adellz Dall. 
“Animal naked, about 16 mm. long, of a dark plum color, 
mottled with fine vermiculate spots of golden yellow; general 
form that of D. carnosum Cuvier, but with a shorter velum, half 
as long as the body and transversely truncate behind; the poste- 
rior portion of mantle short, obscurely bilobed, and without a 
flagellum; front edge of the velum slightly excavated; parapodia 
wide, the sole slightly longer than the body; shell internal, sub- 
conical, white covered with a brownish epidermis; pillar strong, 
reflected with a deep groove outside of it, the basal end project- 
ing spur-like; nucleus small, depressed.’’—Dall, Nautilus 8:73. 
Type locality: —Eagle Harbor, Puget Sound, in 30 fms. (Miss 
Adella M. Parker). 
1663 Genus Epiphragmophora Doering 1875. 
Pilsbry (Nautilus 8:81) states this is the earliest name used 
for Arionta, Aglaia and Euparypha of American writers. 
1664  Epiph. ellipsostoma Pilsbry, Nautilus 8:81. 
Type locality:—‘‘San Juan del Norte’’ (Gabb), probably on the 
east coast of Lower California. 
1665 Lepidopleurus percrassus 
‘Shell solid, strong, small, of a pale pinkish-brown with a 
darker brownish girdle which appears rather narrow in the dry 
state; scales very minute, partly dehiscent, chaffy, with occasional 
slender spinules resembling hairs; scales on the base crowded, 
minute, sandy; an extension of girdle is prolonged between the 
valves on each side as far as the jugum, the surface of these 
sinuses is also minutely scaly with occasional spinules; valves 
thick, white below, moderately arched with the prominent jugum 
forming a sort of keel; near the points of insertion the valves 
are heavily callous below; the sutural lamine are short, smooth 
and separated at the median sinus by a prolongation of the jugum 
in advance of the anterior margins of the pleurz; sculpture of 
the jugum consisting of punctate fore-and-aft parallel grooves 
with some small elevated transverse ridges anteriorly; the rest 
of the valve has, on each side, 6 or 8 vermicular ridges divari- 
cating toward tne posterior edge of the valve and irregularly cor- 
rugated with sharp, fine, elevated lamellze crossing the inter- 
spaces transversely but fading out on the ridges; head-valve with 
minutely nodulous concentric ridges; tail-valve highest at the 
subcentral, not very prominent mucro, in front sculptured like 
the intermediate valves, behind the mucro like the head-valve. 
Length about 14, width 5.75, height 2.5 mm., in the dry state. 
The dry girdle about 0.5 mm. wide.’’—Dall, Nautilus 8:90. 
