’ 
235 
triangulari, inaequilaterali, postice subbiangulata, valvulis sub- 
ah natibus prominulis; epidermide tenebroso-fusca; denti- 
bus cardınalibus grandibus; lateralibus brevibus rectisque; mar- 
garita alba._Diam. 0,5, long. 0,8, lat. 4,1“. Nord-Carolina. — 
U. tampicoensis t. ovata, inflata, transversa, snbearinata inae- 
quilaterali; valvulis crassis; natibus subprominulis; epidermide 
nigricante; dentibus cardinalibus magnis; lateralibus longis, sub- 
rectis magnisque; margarita alba et iridescente, raro rosea. 
Diam. 1,7, long. 2,8, lat. 4,3”. Mexico. — U. Cumberlandia- 
nus t. elliplica, transversa, inaequilaterali; valvulis tenuibus; 
natibus prominulis, epidermide lutea, radiata; dentibus cardinali- 
bus parvis, lateralibus longis rectisque; margarita alba et irides- 
cente. Diam. 0,5, long. 0,8, lat. 4,5“. Cumberland River, Ten. 
— U. simus testa ovala, transversa, compressa, inaequilaterali, 
postice subangulata, valvulis suberassis; natibus prominulis; epi- 
dermide luteola, radiata; dentibus cardinalibus parvis; lateralibus 
longis erassisque; margarita alba et iridescente. Diam. 0,6, long. 1, 
lat. 1,7“, Cumberlant River, Ten. — U. Roanokensis t..sub- 
oblonga, transversa, inaequilaterali,- postice biangulata, compressa, 
valyulis erassis; nalibus prominulis; epidermide tenebroso-fusca ; 
dentibus cardinalibus parvis; lateralibus longissimis subeurvisque; 
margarita alba. Diam. 1,2, long. 2,2, lat. 4,7. Nord- Carolina. — 
U. notatus t. elliptica, compressa, transversa, inaequilaterali, 
postice subbiangulata; valvulis tenuibus; natibus subprominulis; 
epidermide rufo-fusca, vittata; dentibus cardinalibus parvis; late- 
ralibus longis subeurvisque; margarita salmonis colore tincta et 
iridescente. Diam. 0,6, long. 1, lat. 1,5“. Cumberland River. — 
U. Jayanus t. angusto-elliplica, transversa, valde inaequilaterali, 
postice subangulata, valyulistenuibus; natibus prominulis; epider- 
mide fusca; dentibus cardinalibus compressis; lateralibus longis 
rectisque; margarita purpurea. Diam. 0,8, long. 1,2, lat. 2,5. Flo- 
rida. — U. hopetonensis t. suboblonga, transversa, inaequila- 
terali, compressa, postice biangulata, ad latus planulata; valvulis 
suberassis; natibus prominulis, ad apices undulatis; epidermide 
tenebroso-fusca; dentibus cardinalibus parvis; lateralibus longis 
euryisque; margarita purpurea etiridescente. Diam. 0,9, long. 1,7, 
lat. 3,4“. Hopeton bei Darien. — U. lugubris t. elliptica, trans- 
versa, subinflata, inaequilaterali, postice biangulata; valvulis sub- 
crassis; natibus prominulis; epidermide nigricante; dentibus car- 
dinalibus compressis;; ieh sublongis subcurvisque; marga- 
rita purpurea. Diam. 0,9, long. 1,3, lat. 2,5”. Hopeton bei Darien. 
—_ D. arnesianus t. subtriangulari, compressa, inaequilate- 
rali; valvulis erassis; natibus prominulis; dentibus cardinalibus 
arvis; lateralibus subrectis; margarita alba et iridescente. D. 0,6, 
ong. 4, lat. 4,4“. Cumberland River, Ten. — B. Zieglerianus 
t.elliplica, transversa, inaequilaterali, glabra, yalvulis su berassis, nati- 
bus subprominulis,undulatis, epidermide lutea, radiata, dentibus car- 
dinalibus parvis, lateralibus parvis subrectisque; margarita purpurea 
etiridescente. D.0,4,1.1,lat. 1,6%. Cumberland River. — U.crepe- 
rus t. subelliptica, transversissima, valde inaequilaterali, valvulis 
suberassis; natibusprominulis, undulatis; epidernude viridi; dentibus 
16 * 
