42, CRETACEOUS GASTROPODA 
1. Preroponta (?) TEREBRALIS, Stoliczka. Pl. V, Figs. 6—8. 
Pt. (2) testa elongata, fusiformi, anfractibus subplanis atque levigatis ; apertura 
oblique trapezoidali, antice in canalem rectwm et moderate longum extensa; labro 
interne pliciforme incrassato, plica multidentata, ad intervalla impressiones nonnutlas 
in anfractibus superioribus formante ; columella solida, biplicata. 
Spiral angle 22°—25°; sutural angle 12°—16°. 
Probable height of last whorl : total of shell (consid. as 1:00) 0:21 to 0-23. 
An elongated fusiform shell, composed of numerous flattened volutions, the 
surface of which is perfectly smooth, as seen from fragments of the preserved shell. 
The last whorl is very much shorter than the spire, exceeding only by a little the fifth 
part of the total height. The aperture must have had an oblique trapezoidal shape, 
provided anteriorly with a moderately produced canal. The columella is solid with 
two very oblique folds, which become almost obsolete at the mouth. Judging from 
a cast specimen (Fig. 8, on Pl. V.) which appears to be nearly complete, the outer 
lip seems to have been only slightly expanded. The internal varix was long and 
provided with about six teeth, the middle ones being the strongest. There are 
usually three impressions of the former varices traceable on the last whorl, each at 
one-third distance in the circuit; on the penultimate whorl, there are generally but 
two of the impressions, and higher up they disappear altogether. This seems to 
be a similar case to that noted by Pictet in his two species, apparently belonging 
to the same sub-division of Pferodonta. 
Localities. West of Odium in a brownish ¢aleareous sandstone, and east of 
Parchairy in a yellowish arenaceous limestone ; rare. 
formation. Ootatoor group. 
2. PTERODONTA BULIMOIDES, Stoliczka. Pl. V, Fig. 5. 
Pt. testa exigua, buliniformi, elongata, apice obtusa; anfractibus septenis, con- 
vexis, accumulatis lavigatisque; apertura angulate-ovata, antice paulo emarginata ; 
labro in specimine unico haud expanso, interne ad intervalla costato ; columella solida. 
Spiral angle about 40°; sutural angle 5°. 
Height of last whorl : total of shell (consd. as 1:00) 0°37. 
In external shape this small shell recalls very much the form of a Bulimus or 
Achatina. Although only eleven mm. high it numbers seven volutions, of which the 
last one is little more than one-third of the total height. The apex is obtuse, the 
whorls convex, with strongly impressed sutures, the surface covered with fine strize of 
erowth. The columella is solid; the aperture oval, pointed on both ends and anteriorly 
slightly notched. It is evidently a young shell, and we do not wonder, therefore, 
that the outer lip is not perceptibly expanded. The inner fold-like varices are, 
however, certainly present, as may be seen by an inspection of Fig. 5b. on PL. V. 
The relative position of these varices could not be ascertained, for it could not 
be done without the destruction of the unique specimen, the rock, in which it is 
bedded, being a loose gritty sandstone. From the bulimoid form and the large 
