108 MALONE JURASSIC FORMATION OF TEXAS. [bull. 266. 
inclined forward on the flanks, somewhat enlarged on the umbilical 
border, those of the earlier whorls very close and bifurcating or 
sometimes trifurcating at about the middle of the flank into feebly 
diverging smaller ones, an occasional rib remaining simple and then 
being usually accompanied by a short, independent rib, correspond- 
ing with one of those produced by bifurcation, this ornamentation 
becoming gradually obsolete on the greater part of the height of the 
flanks and also on a narrow median zone in the more mature portion 
of the shell, which portion is also usually encircled with large shal- 
low constrictions at remote intervals; the ventral ribs about equal to 
the intervals between them. 
Measurements. — The maturer aspects of the shell are represented 
only by fragments; the cross seel ion of one of which has a height of 
47 mm. and a breadth of 27 mm. 
Occurrence. — The type material consists of several imperfect speci- 
mens and various fragments, all collected by Doctor Stanton in 
foothills near the railroad, at the northwest end of Malone Mountain, 
about 2 miles cast -southeast of Finlay station. Material obtained on 
the west side of Malone Mountain, from No. 18 of Malone Mountain 
section, includes a very doubtful fragment of this species from about 
'J, miles west of Malone station, and a specimen, also doubtful, and a 
fragment from a point about three-fourths of a mile farther south. 
That collected l.\ miles east of Malone station includes a fragment 
which not improbably belongs to this species. 
The septal line of P. schucherti is of the same general pattern as 
that of I\ inconditus Font., as figured by de Loriol," but differs from 
it by its broader first lateral lobe and in other details. The shell of 
P. schucherti also differs from that of P. inconditus in that the latter 
has trifurcate and even sometimes quadrifurcate ribs, the ribbing on 
the flanks of the inner whorls being very much closer in P. schucherti 
than in either inconditus or l><it<l<rux. 
The second specimen above mentioned is larger and less compressed 
than the others and has the ribs less inclined forward on the venter, 
and on part of the shell almost radially directed. I am uncertain 
whether it belongs to P. schucherti or is the young of a larger species. 
The ribs are, however, obsolete on the flanks, and the specimen is 
therefore referred here provisionally. It gives the following measure- 
ments: Greatest diameter, 125 mm.; span of umbilicus, ,50 mm. 
height of outer whorl in intermediate part, 45 mm.; breadth of same 4 , 
SO mm. It is without constrictions, and in form and character of 
ventral ribbing bears a resemblance to Olcostephanus potosinus C. 
and A., a fossil from which in other respects it widely differs. 
The species is named for Mr. Charles Schuchert, curator of inverte- 
brate paleontology in the United States National Museum. 
Foss. d. Baden, PI. XI, flg. lc. 
