1876. | NATURAL SCIENCES OF PHILADELPHIA. 189 
Mesodon major, Binn. 
This species (or form of albolabris) was found he me near Aiken, | 
S. C., but still larger specimens, at Macon, Ga., in the City Ceme- 
tery, by Mr. H. 8. Crooke. The form seems to inhabit a narrow 
strip of territory east of the mountains from Abbeville, S. C., to 
the Gulf of Mexico. The largest specimen I have ever seen is 48 
mill. in its greater diameter. 
The jaw, lingual dentition, and genitalia agree with those of 
albolabris. Fig.1,of plate VI., represents the genital system of 
one individual examined, in which the ovary is very small, and the 
genital bladder unequally divided, both points differing from those 
of other individuals examined. ‘This shows us we should allow 
some latitude of variation in the details of the genital system of 
any given species. 
‘Aglaja fidelis, Gray. 
Oregon. Mr. O. B. Johnson. 
On pl. VI., fig. p, I give a more satisfactory ae of the geni- 
talia of this species than formerly published by me. The organ a 
in the specimens recently examined was greatly developed. The 
organ is a dart sac, which contained a dart of the type described 
below under Arionta Mormonum. 
Arionta Mormonun, Pfr. 
Tulumne Co., California. Mr. A. W. Crawford. 
Pl. VI., fig.s, represents the genitalia. The general appearance 
is that of A. fidelis, as formerly described by me (see below), but 
_there is an additional accessory organ (q.), of use unknown to me. 
The organ, 7, is a dart sac. The dart is short, stout, straight, 
‘Swollen at its base, and with an enlarged acutely pointed apex 
(pl. VI., fig. kK). Upon the vagina, above the insertion of the penis 
Sac, is a ridge-like process (s.) containing in three individuals 
examined one round, and one oblong calcareous nodule (pl. Wile. 
fig. J). I suspect the organ 14, noticed in fidelis (Proc. Acad. Nat. 
Sci. Phila., 1873, pl. L., fig. 5) corresponds with this process. 
Jaw as tiene in Aniorital T ribs. 
Lingual membrane (pl. VI., fig. B) as usual in Arionta. Teeth 
50—1—50, with 15 laterals, the 16th tooth having its inner cutting 
point bifid. 
Arionta sequoicola, J. G. Coop. 
Santa Cruz, California. Mr. H. Hemphill. 
_ The genital system (pl. VI., fig. R) is like that of Arionta Traski. 
