bh a PROCEEDINGS OF THE NATIONAL MUSEUM. A0Y 
have attempted to indicate in the text the degree of inflation, sculpture, 
character of epidermis, and color pattern, character of teeth, nacre, and 
other points of interest. 
I have followed Mr. Lea in the terms used in measurement and desig- 
nation of parts of the shell, calling that part of it which is in the ad- 
vance when the animal is traveling the anterior, and the opposite end, 
which bears the ligament, the posterior. The distance from the anterior 
to the posterior margins Mr, Lea calls the breadth or width; that from 
the base or ventral region to the beaks the length. I prefer the arrange- 
ment of Broderip and Sowerby, which is followed by Conrad and other 
American conchologists, of terming the distance from the forward to 
the hinder part of the shell the length, and that from the wnbones to 
the base the height or width, but have thought if perhaps best to use 
the terms of our great authority on the Unionidae. 
| have only described such species as to my knowledge have been 
ollected in the State of Florida, as it was necessary to fix some limit 
to the list. Many other species, however, are noticed in outlining the 
groups to which the Florida shells belong. 
There are no doubt errors in the work I have undertaken, since much 
of this is a matter of judgment, and human judgment is liable to error 
in the determination and arrangement of many of these exceedingly 
close and puzzling forms. My aim has been to reduce to order the 
chaos in which [ found our southeastern Unionidae, and throw some 
light on the limits of the species, their relationships, and distribution. 
GENUS UNIO. 
GROUP OF UNIO INFUCATUS. 
The species which typifies this group seems to stand alone among 
American unios. U. corrugatus of India resembles it somewhat in sculp- 
ture and general form, but is more inflated and has a less solid hinge. 
U. infucatus in general form is very close to U, ienticularis and U, 
chickasawhensis, but is characterized by peculiar chevron-shaped and 
more or less nodulous corrugations, in some cases covering the entire 
shell. The former species varies greatly in the. amount of sculpture, 
even to specimens which are nearly smooth, much as U. pustulosus va- 
ries into the smooth forms of Schoolcrafti, and it is possible that the 
present group should be merged with that of U. chickasawhensis.* The 
general form is lenticular, the color dark brown to black, the teeth and 
hinge plate rather solid, with nacre varying from white to lurid purplish. 
Unio infucatus Con. 
Unio infucatus Con, (Plate xix. Figs. 1, 2,5.) New I. W. Shells, pl. 111, fig. 2. 
Unio Kleinianus Lea, (Plate xix. Fig.6.) Obs. v, p. 21, pl. xvit, fig. 18, Mar. 5, 
' 1852. Type, Suwanee R., Fla., collected by Maj. Le Conte, West llorida; coll, 
of Wm, A. Marsh. 
"Since writing the above the examinationof a large amountof additional material 
has convinced me that this species groups with U. chickasawhensis. 
