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32 THE AMERICAN MIDLAND NATURALIST 
THE NAIADES OF MISSOURI.—VII. 
BY WILLIAM I. UTTERBACK. 
Eurynia (Micromya) lienosa (Conrad.) 
(“Little Spectacle Case.’’) 
PID DOA GAR peso GG At 1): 
1834— Unio lhenosus Conrad, An. Jl. Sci., XXV, p. 339, pl. 1, fig. 4. 
1900b—Lampsilis lienosus Simpson, Pr. U. S. Nat. Mus., XXII, p. 547. 
1912b—Eurynia (Micromya) lenosa (Conrad) Ortmann, An. Car. 
Mus., VIII, pp. 340 and 341. 
ANIMAL CHARACTERS. 
NUTRITIVE STRUCTURES:—Branchial opening with two-ranks 
of papillae; anal crenulated; supra-anal high, small, closely 
connected by mantle edges to anal; inner laminae of inner gills 
more or less free from the visceral mass; palpi subfaleate connected 
antero-dorsad about one-half of their length; color of soft parts 
soiled white except mantle’ edge of siphonal area blackish, gills 
brownish. 
REPRODUCTIVE STRUCTURES:—Marsupium  kidney-shaped, 
restricted to posterior half of outer gill, consisting of twenty-five 
distinct ovisacs, which, when gravid, distend transversely in middle 
and ventrad as white beadlike bodies; inner mantle edge of females 
antero-ventrad to branchial opening with eight to ten conical 
tentacles rather wide apart and reaching a little over half way 
centrad-ventrad; conglutinates large, club-shaped; glochidia large, 
subovate, measuring 0.220 x o. 270 mm. 
SHELL CHARACTERS. 
EXTERNAL STRUCTURES:—Shell small, elliptical, moderately 
inflated, thick; post-umbonal ridge rounded; disk smooth; umbones 
low sculptured with inverted V-shapes; epidermis reddish brown 
with dark banded rays; female shell expanded post-ventrad, male 
rather biangulated behind. 
INTERNAL STRUCTURES:—Cardinals double in left, single in 
right valve; laterals also double in left, single in right; inter- 
dentum lacking; beak cavities moderately deep; nacre purplish 
with old gold and copper-color in branchial cavity. 
Sex Length Height Diameter Locality 
OM ES OUP e sO, ok. 2me5 mam Black R., Williamsville) 
aA 
( 
G50: x 30 x (2ofomm (o aaee ey ) 
Cl Aaa 20" exon sOTli am Aca ay ) 
DEN Ox Toe jb ODT ae ee ae ) 
