512 PROCEEDINGS OF THE NATIONAL MUSEUM. voi.xxiv. 
GASTROPODA. 
Genus ACT^^ON MoMtfort. 
Subgenus MICROGLYPHIS Dall, 1902. 
ACT.^ON (MICROGLYPHIS) BREVICULUS, new species. 
Shell small, short, plump, j^ellowish white, with four and a half 
polished whorls; nucleus sinistral but wholly immersed, so that the 
apex seems as if dextral, smooth; whorls convex, rapidly increasing, 
separated by a deep, almost channeled, very narrow suture; sculpture 
of extremely faint, line spiral striae almost a]>sent in front of the suture 
and growing- more distinct anteriorly, not visibly punctate; aperture 
ample, outer lip simple, body with a well-marked callus, continued 
on to the pillar and spreading a little over the base behind the pillar, 
which is concavely arcuate, its anterior edge thickened and expanded 
into a strong spiral plait or lamina behind which on the pillar is a sec- 
ond less marked plait; in front of the pillar is a small l)ut distinct 
notch; Ion. 3.6; max. diam,, 2.25 nmi. 
Dredged off Santa Rosa Island, California, in 53 fathoms, sandy mud, 
at station 2902, by the U. S. Fish Commission steamer AJbatross; 
bottom temperature, 45° F. U. S. N. M. , 109042. 
This little species belongs to a group of chiefly deep water Actseons, 
characterized by a very short spire and globose shell in which the end 
of the pillar is not only truncate as in Rictaxia^ but has a marked sul- 
cus behind it and is produced laterally into a rather wide spiral flange 
at maturity, and is co-ncave with a single feeble plait l)ehind the ter- 
minal lamina. Of these, A. 2y<it"co7ilcus and A. curtulus Dall may be 
mentioned, the latter, from the western part of Magellan Strait, may 
serve as type for the group which may be regarded as a sul>genus of 
Actcecni and take the name of MicroglyjjJus. The present species is dis- 
tinguished from A. curtulus by its somewhat more elongate form and 
much less obvious sculpture, beside being somewhat larger and less 
delicate. 
TOLEDONIA, new genus. 
Shell small, smooth, thin, imperforate, succineajform; pillar con- 
tinuous with the basal margin of the aperture, straight, but with an 
elevated thin plait near the base of the pillar, which appears to be 
continued into the coil of the shell; nucleus smooth, dextral; soft 
parts unknown. Type, 7'. perplexa Dall. 
This little shell has a combination of characters which prevent its 
being assigned to any known genus. It differs from any of the 
FyrainldeUidm in its form and dextral nucleus; from the Actceonldm 
by its peculiar pillar and dextral luicleus; from immature Rlngicula 
by its single plait and general aspect. It is not certain even to what 
