SPHENODISCID.E. tal 
well as the fact that the sides are smooth and entirely without tubercles, 
also separate it from plewrisepta. 
The diameter is not far from 114 mm. The partly preserved living 
chamber of the largest cast is not less than one-half of a volution in length. 
About midway the diameter from line of involution to venter is 68 mm., that of 
the same volution opposite this, partly estimated, is 44 mm., the umbilicus 
being only 2mm. The keel was solid in the ephebic stage. The basal suture 
and the next or second one are apparently incomplete on the right side, but on 
the left they are both present but depressed toward the umbilical shoulders. 
The last three sutures are more closely approximated than others, as if the 
shell were in the gerontic stage. 
The sutures have minute marginal lobes on the saddles and lobes. 
The first lateral saddles are very short and broad and quadrifid, the mar- 
ginal saddles are small, but still distinctly subphylliform, as are also the 
second, third, and fourth; the fifth is distinctly phylliform and _ bifid, the 
sixth just beginning to be bifid on the left side, while on the right side it is 
still entire.’ The remaining saddles form the usual series, flattening out on 
the bases near the umbilicus. On account of the short saddles the sutures 
are as widely separated on the venter as in lobatus, but a slight overlapping 
begins at the third ventrals and continues to the umbilicus, in so far as the 
sutures were seen in this direction. The smaller specimen has even broader 
and stouter saddles, but the umbilicus is not so much contracted. There 
were five divided saddles on the left side of this specimen and six on the 
tight side, just the reverse of the larger fossil. 
Locality: Eighteen and one-half miles southeast of Eagle Pass, Texas 
Age: Eagle Pass beds, Upper Cretaceous. 
SPHENODISCUS LENTICULARIS (Owen). 
Pl. VII, figs. 1, 2; Pl. IX, figs. 1-6. 
Ammonites lenticularis Owen, 1852, Rept. Geol. Surv. Wisconsin, lowa, and Minne- 
sota, p. 579, pl. 8, fig. 5. 
Placenticeras lenticulare Meek (pars), 1876, Mon. U. S. Geol. Surv. Territories, 
Vol. IX, fig. 66 on p. 473 and pl. 354. 
Meek’s original specimen, from which his figures were taken, shows 
that these are accurate with exception of certain minutiz. Figure on page 
a The sixth column of saddles was entire on the left side throughout; on the right it was just 
beginning to show a dividing marginal, the diameter of the side along this line being about 53 mm. 
