Os eS 
aes 
a. PROCEEDINGS OF THE NATIONAL MUSEUM. - 425 
GROUP OF UNIO PARVUS. 
A group of small and usually well characterized shells, distributed 
throughout the entire Mississippi Basin, the Gulf drainage, and in that 
portion of the Atlantic Slope from South Florida to North Caroiina. 
In form they are oval, or obovate to oblong, usually rounded before and 
behind, rather inflated, with generally dark and lusterless epidermis, 
though it is sometimes smooth, shining, and rayed. The beaks are 
-undulate; the teeth usually compressed and often curved; the nacre 
is almost always brilliant, silvery, bluish, and iridescent, though a few 
of the species have dark and lurid interiors. 
Unio minor Lea.” 
(Plate Lxvu, Fig 2.) 
Unio minor Lea, Obs. Iv, p. 34, pl. xxxrx, Fig. 3. Aug. 18, 1843, Lakes Monroe and 
George; S. B. Buckley. 
An interesting species and one of the very smallest, an adult be- 
fore me from Lake Monroe, one of Lea’s types, being 0.9 inch in width 
and 0.6 inch in length, while others from the same locality, in Mrs, An- 
drews’s collection, are 1.50 inches in width by 0.80 inch in length. The 
species is regularly obovate in form, inflated and wedge-shaped when 
viewed from the base; being of greatest diameter in the neighborhood 
of the beaks and tapering to the posterior end. The epidermis is 
rough and black; the nacre bluish and iridescent behind; the teeth are 
rather strong, as the substance of the shell is quite solid. 
This shell is sometimes mistaken for U. marginis, but is darker 
colored, solider, more inflated, and rather wider. Dr. Leadid not know 
whether the beaks were undulate or not, and all the numerous speci- 
mens I have seen are so eroded I can not tell certainly, but it is probably 
like the rest of the group in this respect. Three shells before me, be- 
longing to Mrs. Andrews, are from the Edisto River, South Carolina, 
and [ found it in Horse Creek, Manatee County, in latitude 27°. 
Unio vesicularis Lea. 
(Plate Lxvul, Fig. 4.) 
Unio vesicularis Lea, Obs. xii, p. 41, pl. x11, Fig. 34. Sept. 15, 1873, Okechobee; Dr. 
Budd and C. M. Wheatley. 
Lea described this species from very poor material, two worn, badly 
eroded opposing valves and a smaller pair in poor condition. These 
vary from light to dark olive green and are slightly rayed. A worn 
specimen in Lea’s collection from Lake George, labeled by him Unio 
amygdalum, scarcely differs from the opposing valves which are his 
type of vesicularis. It is a trifle less wide and not quite so inflated. I 
*There are two Unios in the Museum collection (No. 91130) from Blue Springs 
Landing, Fla., received from Mr. B. H. Wright and labeled by him Unio Stearnsiana 
Wright, which are typical examples of Unio minor Lea, 
