428 NOTES ON FLORIDA UNIONIDA—SIMPSON. 
Unio obesus Lea. 
(Plate Lxvill, Fig. 6; Plate Lx1x, Figs. 1, 2,4; Plate Lxx1, Fig. 3.) 
Unio obesus Lea, Obs. 1, p. 106, pl. xi, Fig. 26. May 7, 1830. York River, Va.; 
Wm. Cooper. 
Unio Blandingianus Lea (Plate Lxx, Figs. 1, 2), Obs.1, p. 213, pl. xv. Fig. 44. Feb. 7, 
1834. 
Unio paludicolus Gould (Plate Lxx1, Fig. 2), Proc. Bost. Soc. Nat. Hist., Aug. 15,1845 
Everglades. 
Unio Jewettii Lea (Plate Lxx1, Fig. 1), Obs. x1, p. 36, pl. xxxvul, Fig. 89, June 2, 1868, 
Sink of Noonans Lake; Col. Jewett. 
Unio rivicolus Conrad., Am. Jour. Conch. Iv, p. 280, 1868. Brook near Tampa, Fla. 
Unio Webdsteri B. H. Wright (Plate Lxx, Fig. 3), Proc. Acad. Nat. Sei. Phila, 1888, p. 
113, pl. u, Fig. 2. Lake Woodruff, Volusia County. 
This species, though varying less than many others, has unfortunately 
received a great number of names. The form is that described with 
the group; in the type it is somewhat inflated and rounded ventrally; ~ 
the epidermis is never smooth, varying from ashy and greenish olive to 
jet black; the scaly or laminated covering of the very dark examples 
is often glossy. In Lea’s collection of obesus some of the specimens 
have a reddish epidermis, and it is this variety, I think, that Mr. 
Wright has described as U. Websteri. A shell collected in Lake Wood- 
ruff, so labeled by him, and donated to the Museum (Museum No. 91128), 
is undoubtedly U. obesus. U. rivicolus Con., judging by his figures and 
description, is identical with the form Lea described as U. Blandingi- 
anus; the variety with rough, glossy epidermis, often becoming some-— 
what arcuate with age. U. Jewettii, though sometimes shaded with 
green and partially rayed, connects these forms with the type. U. palu- 
dicolus, judging from Gould’s description and shells that he sent Lea 
from the typical lot, appears to be the young or perhaps a dwarf form 
of the species under consideration. Such a form, somewhat widened 
posteriorly, was found abundantly by the writer in Manatee County, 
and I have the same before me from several localities. Some of these 
from Spring Creek, belonging to Mrs. Andrews, have reddish chestnut 
epidermis and salmon coppery nacre, yet they are, no doubt, a variety 
of the above.* It is very doubtful whether U. declivis and columbensis 
are anything more than forms of this species. Both generaily have a 
couple of shallow furrows running from near the beaks down the dorsal 
slope, but this feature is sometimes seen in the varieties I have noticed. 
The former is occasionally nearly smooth, suggesting U. camptodon and 
manubius. The latter is generally a wider shell than the type. It may 
be said that the obesus form is found along the Atlantic slope, from 
*T have paeautly received from Mr. Charles W. Johnson four specimens of what — 
are undoubtedly Unio obesus, two of them from Pemberton’s Ferry, on the.Withlacoo- 
chee River, Florida, the others from a tributary of the St. Johns, the largest of which 
measures 1} inches in width by seven-eighths inch in length; yet they are all quite 
solid shells and evidently adults. They are almost perfect representatives in min-— 
iature of some of Lea’s very largest specimens of the species. I give a figure of one 
of them. 4 
fe ES 
