196 
second with two strong spiral cords which divide the space he- 
tween the sutures into three equal areas. Post-nuclear whorls 
appressed at the summit, strongly sloping shouldered, ornamented 
with two strong spiral keels, which divide the space between the 
sutures into three equal areas, and very strong, vertical, axial ribs, 
16 of which occur upon each of the turns. The intersections of 
the axial ribs and the spiral cords form strong elongated tuber- 
cles, the long axes of which coincide with the spiral sculpture. 
These tubercles slope more abruptly posteriorly than anteriorly. 
The intersections of the axial ribs and the spiral cords inclose 
shallow squarish pits. Sutures weakly impressed. Periphery of 
the last whorl marked by a strong keel to which the axial ribs 
extend feebly. This keel is a little nearer to the first post-periph- 
eral keel than that is to its posterior neighbor. Base moderately 
long, marked by two very strong keels, which divide the space 
between the peripheral keel and the tip of the columella into three 
equal areas, the spaces between the keels being very deep and a 
little wider than the keels. Entire surface of the spire and base, 
inclujing the ribs and intercostal spaces, crossed by numerous, 
fine closely spaced, spiral striations. Aperture irregular, chan- 
neled anteriorly; posterior angle obtuse; outer lip thick within, 
thin at edge, rendered sinuous by the exernal sculpture; colu- 
mella stout, strongly twisted and reflected; parietal wall glazed 
with a thick callus.’’—Bartsch. 
3026 Bittium (Lirobittium) catalinense 
“Shell elongate-conic, milk-white. Nuclear whorls a little 
more than one, marked by two strong spiral cords which divide 
the turns into three equal areas. Post-nuclear whorls shouldered 
at the summit, marked by three nodulose spiral keels; one of 
these, which is a little below the summit, is less strongly devel- 
oped than the other two on all but the last turn; on this turn it 
is practically equal to the others. In addition to the spiral keels, 
the whorls are marked by rather strong, well-rounded axial ribs 
which are about two-thirds as wide as the spaces which separate 
them. Of these ribs, 16 occur upon the first to fifth, 18 upon the 
sixth and seventh, 20 upon the eighth, and 24 upon the penulti- 
mate turn. The intersections of the axial ribs and the spiral cords 
form strong cusp-like nodules, which are suddenly truncated pos- 
teriorly and slope gently to the succeeding cord anteriorly. The 
space between the summit and the truncated end of the first row 
of tubercles forms a strong shoulder. The spaces inclosed be- 
tween the spiral keels and the axial ribs are moderately impressed 
rounded pits. Sutures strongly constricted, showing the greater 
part of the peripheral cord on all the turns. Periphery and base 
of the last whorl marked by five spiral cords which grow suc- 
cessively weaker from the periphery to the umbilical area. These 
cords are truncated on the posterior margin and slope gently an- 
teriorly until they fuse with the general surface of the shell. Ap- 
erture irregular, channeled anteriorly; posterior angle obtuse; 
outer lip rendered sinuous by the external sculpture; columeila 
oblique, somewhat twisted; parietal wall glazed with a thin cal- 
lus.’’——Bartsch. 
Type locality:—Pleistocene, Santa Barbara, Cal. 
3027 Variety inornatum 
Type locality:—Catalina Island, Cal., in 40 fms. 
3028 Bittium (Lirobittium) ornatissimum 
Shell elongate-conic, creamy-white. Nuclear whorls one and 
