130 Trans. Acad. Sci. of St. Louis. 
surface polished and the lines of growth not distinct. The 
embryo is small, obtuse, smooth and paucispiral, consisting 
of about a single whorl. Plewrotoma is represented by a 
moderate number of species confined to the Indo-Pacific region, 
such as babylonia Linn., crispa Lamk., grandis Gray and 
garnonst of Reeve, and is a recent development, not occur- 
ring, as far as known to me, in the fossil state. It probably 
exists, however, in the unexplored upper Tertiaries of those 
regions. 
Lophiotoma n. gen. 
Although having the small smooth embryo of a single 
whorl, polished surface and obsolete lines of growth, charac- 
terizing Pleurotoma, this genus may be recognized at once 
by the relatively shorter and stouter form as a rule, less 
elongate and straighter beak, which is strongly tapering in cer- 
tain large forms like wnedo, finer, more acutely elevated and less 
close-set spiral carinae, with a usually distinct and even, finely 
lineolate concavity from the peripheral carina to the suture or 
subsutural collar, the latter being generally present and by 
the deep anal sinus formed centrally on, and not behind, the 
peripheral carina, the latter being more strongly elevated and 
usually subduplex. The genus is exclusively recent, com- 
posed of large species inhabiting the Indo-Pacific region and 
is represented in my cabinet by éigrina, virgo and marmorata 
Lamk., wnedo Val., jickeli Weink., leucotropis A. et R. and 
the following : — 
General form and ornamentation similar to tigrina but more slender, the 
dark brown spots very minute aud sparse, but similarly di-tributed, the 
duplex peripheral carina more strongly elevated and the anal sinus deeper 
and narrower. Length of a specimen having 12 body whorls, 59mm.; 
width, 18 mm. Cebu, Philippine Islands......... -microsticta n. sp 
Pieuroliria De Greg. 
This genus, originating in the middle Eocene and coming 
down to the present time, is the American homologue of 
Lophiotoma, but is composed of much smaller species having 
a slender form, very characteristic sculpture of two to three 
strong spiral carinae, the peripheral bearing the small anal 
