438 THE AMERICAN MIDLAND NATURALIST 
row of papillae on the inner edge extending down quite to the 
central part of the ventral edge. These papillae are often quite 
tentacular and are rather regular and uniform in shape and size 
and are never widely separated as in case of the Micromya mantle 
edge of this anterior branchial border. Its inner laminae of the 
inner gills are usually entirely connected with the visceral mass; © 
however, a small hole is sometimes left at the posterior end post- 
dorsad to foot. 
SHELL CHARACTERS:—In shell characters there are no great 
distinctions to be considered as a group since the chief distinguish- 
ing characteristic is in the post-mantle edge as above discussed. 
Its beak sculpturing is identical with that of the Mzcromya shell 
being sinuated or double-looped, the posterior loops being more 
or less broken behind. 
This group of Eurynia is represented in this State by E. (E£) 
subrostrata and recta, both having rather wide distribution. 
Eurynia (Eurynia) subrostrata (Say). 
(“Common Pond-Mussel,”’ “ Lilliputian.’’) 
PL XV IT Ses) tole AD: 
1831— Unio subrostratus Say, New Harm. Digs. 
1850— Unio mississippiensis Conrad, Jl. Ac. N. Sci. Phila., 1, p. 277, 
Dis SOG Ve tee. ere 
1868— Unio topekensis Lea, Pr. Acad. Nat. Sci. Phila., XII, p. 144. 
1900b—Lampsilis subrostratus Simpson, Pr. U. S. Nat. Mus., XXII, 
Pp. 546. 
1912b—Eurynia (Eurynia) subrostrata (Say), Ortmann, An. Car. Mus., 
Wile ps3 442 
ANIMAL CHARACTERS. 
NUTRITIVE STRUCTURES:—Branchial opening narrowly papil- 
lose; anal finely papillose supra-anal separated from anal by a 
rather short mantle connection; inner laminae of inner gills con- 
nected to visceral mass; palpi rather small and connected antero- 
dorsad about one-fourth of its length; color of soft parts grayish 
with mantle edge along siphonal region blackish. 
REPRODUCTIVE STRUCTURES:—Marsupia kidney (or rather) 
fan-shaped, consisting of twenty large, well defined ovisacs, dis- 
tended, when gravid, at ventral edge thus giving the congluti- 
nates a club-like shape; ventral tips of ovisacs beaded bearing 
bluish pigment with glochidia scattered throughout the sacs; 
