THE . CONCHOLOGISTS’ -: EXCHANGE 75 
38.— Unio securis, Lea. 
Found rarely in the Mississippi River and 
in Swan Lake on the Bog Island, and alwstys 
in deep water. A smooth, triangular shell, 
very solid, and usually very beautiful. Epi- 
dermis smooth, varying from yellow to green 
and brown color. The rays are remarkably 
variable, some being straight, others zigzag 
with blackish or brown dots in all imaginary 
shapes. Its beaks are very much compressed 
and very flat over the summit, while its um- 
bones are very angular. The nacre is usually 
white, shining and iridescent, but I have 
found specimens having pink and salmon- 
colored nacres. Sexual differences are very 
apparent; the female being very much inflated 
and truncated. The species is slow in its 
movements and moves about but little. Secz7s 
is so distinct that when once known it need 
not be confounded with any other. 
39.—Unio Schoolcraftii, Lea. 
This species is found only in Edwards 
Creek and is now rare. It is a pustulose spe- 
cies and in some respects resembles U. puestz- 
Zosus, but the careful observer will notice dif- 
ferences in outline, as it is quadrate, while 
pustuiosus is subrotund and, again, it is always 
much less inflated. It has the same greenish 
tint over the beaks and umbones, but it is 
spread on,so to speak, in a different manner. 
When young, Schoolcraftit has but few pus- 
tules, but as it increases in age (usually), is 
found almost completely covered with them. 
The epidermis is very dark brown in adult 
specimens, ‘The teeth and cicatrices are quite 
different from pzstelosus. The nacre is white 
and shining, always much thicker before than 
behind in all except the very aged specimens, 
in which the nacre is of a rusty iron ore color. 
It is a very active species and may be found 
in all situations; in the iron ore beds, in the 
gravel, in the mud and in both deep and 
shallow water. Often, owing to its activity, it 
gets left upon dry land, as it will venture along 
the margin of the stream where the water is 
not deep enough to cover its shell, and, by a 
sudden fall of the water it is left upon the dry 
sand. Ata place of this kind, below Fender’s 
Grist Mill when the waters are shut off every 
Saturday evening, the collector may find num- 
bers of this species, together with parvus and 
rubiginosus which have been suddenly left in 
the sand by the receding waters. 
To be continued. 
DESCRIPTION OF NEW GENERA 
OR SUBGENERA OF 
HELICIDA. 
BY C. F. ANCEY. 
(Continued. ) 
XVIII. Coxia, Ancey. ‘Testa valde de- 
“planata,latissime wmbilicata, tenuis,subcornea, 
“supra minus micans, infra nitidior, Spira 
‘plana, apice prominulo, arctispirata, anfracti- 
“bus numerosis, ultimo supra acute angulato, 
“infra convexo. Apertura parva, sinuata, ad 
“carinam angulata. Peristoma obtusatum, vix 
“inferne expansiusculum,”’ 
Type: Helix Macgregori, Cox, 
Geog. distribution: New Ireland. 
This group differs from Systrophia and from 
Ophiogyra in being carinated above the peri- 
phery and in having the apex elevated above 
the level of the following whorls. ‘The dis- 
tribution is not the same. 
XIX. Lejeania, Ancey. “Testa forma 
*‘Xerophilis quibusdam sen Fructicolis vicina, 
“tenuis, anfractibus sat celeriter crescentibus, 
““convexo depressa, spira convexa,subobtecte et 
“mediocriter umbilicata, cornea fasciis opace 
“albis zonata vel alba opaca cum zonis angustis 
“nigris. Apertura obliqua; peristoma tenuis, 
“simplex acutum, rectum, ad umbilicum expan- 
“sum.” 
