102 SUPPLEMENT TO GREAT OOLITE MOLLUSCA. 
Movoponta arata, Lye. Tab. XLV, fig. 19. 
Testa trochiformi, spira elevata, anfractibus (6) latis, concavis, postice et antice carina, 
striata, obtusa, suturis valde impressis, anfractibus semel concentrice tenuissime lineatis et 
decussatim oblique striatis ; basi lineis concentricis majoribus et minoribus alternatis ; 
sulco columellart magno et dente obtuso. 
Shell trochiform ; spire elevated ; volutions (6) wide, concave, having a striated obtuse 
keel upon their posterior and anterior borders; there are also very delicate encircling 
lines, which are indented by oblique decussating striations; the base is concentrically 
lineated, the lines being alternately large and small; there is also a conspicuous colu- 
mellar groove and obtuse tooth; the aperture is nearly circular. 
Height and basal diameter nearly equal. 
Geological Position and Locality. The Forest Marble of Laycock ; in the collection 
of W. Walton, Esq. 
Monoponta tecuLata, Lye. Tab. XLV, figs. 17, 15. 
Testa sub-trochiformi, spira elata, anfractibus (4), latis, in medio angulatis, carinis, 
tribus cingendis, superne oblique planatis, inferne concavis, anfractibus semel concentrice 
lineatis, lineis granosis, striis tenuissimis decussatis ; bast concentrice lineatis, sulco magno 
umbilicali et sulco et dente obtuso instructo. 
Shell sub-trochiform ; spire elevated, consisting of four wide and carinated volutions, 
angulated in their middle portions by a prominent encircling keel, a keel being also 
placed at the anterior and posterior border of each volution; between the carine are 
numerous regular encircling lines, rendered granulated by decussating very fine oblique 
striations; the base is concentrically lineated, and has a large umbilical groove bounded 
by a prominent keel; the columellar sulcus and tooth are also conspicuous ; the aperture 
is subcircular, its outer border impressed by the carine. 
The diameter at the base is one third greater than the height. A pretty species, with 
strongly sculptured ornamentation. The volutions are obliquely flattened above and con- 
cave beneath the 1nedian carina. 
Geological Position and Locality. The Forest Marble of Laycock; in the collection 
of W. Walton, Esq. 
OE ee 
