434 THE AMERICAN MIDLAND NATURALIST 
smooth reddish-brown with bright green rays arranged all over 
its shell. ; 
INTERNAL STRUCTURES:—Cardinals double in both valves, 
laterals double in left, single in right; beak cavities rather shallow; 
nacre white or Jight bluish. 
Sex Length Height Diameter Locality 
Cth AGE cy Wiz Mae | Sus faavan (Jack’s Fork of Current R.) 
OF 5) Sls) rom (White R., Hollister) 
OY 3a Ky 10s x SL Thm (Black R., Williamsville) 
eh MOG Sef A'S Gfaaban (Jack’s Fork of Current R.) 
The last measurement is that of a young shell that shows a 
beak sculpture of a profusely double-looped or corrugated ridges 
the latest one being the strongest and running down quite low on 
the disk. 
MISCELLANEOUS REMARKS:—For this State iris is strictly 
a southern shell, being only found in the White and Black River 
- basins. Perhaps this pretty little shell is much more common 
than supposed, since it is so liable to escape observation due to 
its minuteness of size yet its bright green rays of uneroded shells 
make it rather conscpiuous in clear shallow water. It has been 
found to be bradytictic. 
Eurynia (Micromya) brevicula (Call). 
(‘Broken Rays,’’ “Soul-of-Wit.’’) 
PYCXIW Ef Fags N08 ia 
1887— Unio breviculus Call, Pr. U.S. Nat. Mus., X, p. 499, pl. XXVIII; 
Tr. Ac. Sci. St. Louis, VII, (1895) p. 6, pl. XVI. 
1900b—Lampstlis breviculus Simpson, Pr. U. S. Nat. Mus., XXII, 
D.. $33: 
ANIMAL CHARACTERS. 
NUTRITIVE CHARACTERS :—Branchial opening densely papil- 
lose; anal crenulated; supra-anal large, high, well separated from 
anal with thick, spotted mantle edges; inner laminae of inner 
gills not free from visceral mass; palpi rather large, connected by 
their edges one fourth of their length antero-dorsad. 
REPRODUCTIVE STRUCTURES:—Marsupium rather kidney- 
shaped consisting of ten or fifteen ovisacs well separated, with 
bluish ventral border and each ovisac presenting a beaded appear- 
ance of black pigmented spots; in female mantle border antero- 
ventrad to branchial opening with a flap-like structure bearing eight 
