554 ORTMANN—NAYADES OF 
majority of the specimens belonging to oviforme. In Little River, 
at Walland and Melrose, Blount Co., Tenn., it is well developed, 
pure, and not accompanied by oviforme. The Little River form has 
been called striatisswmus, and it has one peculiarity in the soft 
parts ; they are of the orange type, and the placentz are red. P. ovi- 
forme argenteum is also in the tributaries of Hiwassee River (in 
Conasauga Creek with oviforme), and in South Chickamauga Creek, 
at Ringgold, Catoosa Co., Ga. The latter specimens have, in the 
average, a greater diameter, resembling that of oviforme, but they 
are stunted in growth (truncated behind). A few of normal shape 
are clearly argentewm. In the larger rivers, this form is missing. 
Type locality: Holston River, Tenn. (not recently found in Hol- 
ston proper). 
32, PLEUROBEMA OVIFORME HOLSTONENSE (Lea), 1840. 
Unio holstonensis Lea, ’40——Unio mundus Lea, ’57——Unio tes- 
serule Lea, ’61.—Unio pattinoides Lea, ’71—Unio acuens Lea, 
"71 —Umio lawi Lea,’71.—Unio holstonensis and tesserule Lewis, 
*71.—Unio bellulus Lea, ’°72.—Unio acuens and law Pilsbry & 
Rhoads, ’96.—Pluerobema holstonense, acuens, and tesserule 
Simpson, *14, pp. 739, 749, 749. 
U. mundus, lawt, pattinoides, and bellulus have already been rec- 
ognized by Simpson as synonyms of P. holstonense. 
This is the swollen, large river form, of oviforme. U.holstonensis, 
pattinoides, acuens, and lazwi are less swollen than the others (mun- 
dus, tesserule, bellulus), but they all pass gradually into each other 
with regard to obesity. 
This form has been reported from the Tennessee below Knox- 
ville, and down to the mussel shoals in northern Alabama; and fur- 
ther from the lower Clinch, the lower Emory River, and the Noli- 
chucky. According to the material examined by the writer, it goes 
up, in the Clinch, to Edgemoor, Anderson Co., Tenn.; in the Hol- 
ston, to Mascot, Knox Co., Tenn.; it is in French Broad at Boyd 
Creek, Sevier Co., Tenn.; in Little Tennessee River, Monroe Co., 
Tenn. (Walker coll.) ;and in the Hiwassee at Austral, Polk Co., 
Tenn. At all these points, near its upper limit, it is associated and 
intergrades with oviforme. 
