51 
horn color, not radiated ’ flattened and fuscous on the anterior mar- 
gin ; beaks decorticated, placed nearer central ; umbo prominent ^ 
within parlaceous ; cavity of the beaks capacious; primary teeth 
very oblique, almost parallel to the posterior margin and much 
compressed. Length, three inches ; breadth, four inches. 
Inhabits the Ohio river and its tributai^^ streams. 
Encyc. Method, vol. 63, tah. 248, 5. Plate 2, fig. 7. 
Unio cariosus. — Shell moderately thick, much longer before, 
and shorter behind the beaks ; olive green, sometimes radiate with 
green, and with fine interrupted wrinkles placed in longitudinal 
rows, but usually the green radii are wanting, or only visible in the 
anterior margin, and the wrinkled radii indistinct ; in older shells 
the middle of the base is a little shortened ; beaks somewhat promi- 
nent, rather distant, carious, exposing a wax-yellow surface ; con- 
cavity bluish-white, teeth resembling those of the preceding species, 
but the primary ones are not so much compressed or oblique ; they 
are often sub-conic and crenate. Length one inch and a half : 
breadth, two and a quarter. Plate 3, fig. 2. 
Musculus latior, suhfuscus^ Cseruleis lineis Radiatus. Lister^ 
Conch, tab. 152, fig. 7. 
Martinf s figure of U. pictorum resembles this shell in outline. 
Yol. 6. 
Very common in the Delaware and Schuylkill rivers. 
Gmelin, Ed. Syst. Nat. p. 3220, refers to Lister’s figure as a 
variety of Mya radiata, a native of Malabar : but we have ventured 
to consider it a distinct species ; the largest we have seen was 
brought from Wilkesbarre by Mr. Lard. Yanuxem, in length two 
and one-fourth, breadth three and three-fourths inches. The animal 
rarely infested by a parasite. See the article Ilydrachne. 
Unio ochracetjs. — Shell thin, fragile, translucent, subovate, 
hinge margin somewhat rectilinear, color from a pale reddish orange 
to a pale olive ; generally radiate with dull green and with minute 
wrinkled radii; anterior margin very finely wrinkled; beaks de- 
corticated and approximate, with two or three small concentric un- 
dulations ; within bluish- white or ochraceous, tinged with red near 
the base ; teeth very oblique and much compressed. Length one 
inch and a quarter : breath, one and three-quarters. Plate 2, 
fig. 8. 
This shell, in many respects, resembles the preceding, with which 
