40 MOLLUSCA FROM THE GREAT OOLITE. 
CERITELLA Lonetscata, Buv. sp. Plate IX, fig. 14. 
PLEUROTOMA LONGIscATA, Buvignier. Meém. Soc. Philom., Verdun, 1843, pl. 6, fig. 8. 
Testa parvd, turritd, elongata ; apice acuto; anfractibus (9—10) subplanatis ; costis 
longitudinalibus rectis numerosis, carinatis ; carind unicd marginali ; apertura angustata ; 
cauda subrectd. 
Shell smooth, turreted, elongated; apex acute; whorls (9—10) rather flattened, with 
longitudinal, straight, numerous ribs; and a single encircling smooth carina upon the 
upper margin of the whorls; aperture narrow, canal straight, short. Axis 3 lines. 
Locality. his little species accompanies its allied forms in the soft shelly Oolite 
beneath the planking of Mimchinhampton Common. It is very rare. 
CrritELLA RissorpEs, Buv.sp. Plate IX, fig. 7. 
? PLEUROTOMA RISSOIDES, Buvignier. Mém. Soe. Philom., Verdun, 1842, pl. 6, fig. 9. 
Testa parva, turritd ; spird mediocri elata ; apice acuto ; anfractibus angustatis, posticis 
carinatis, carind rotundatd ; costis longitudinalibus, rectis, subincurvis ; anfractu ultimo 
elongato ; apertura angustatd. 
Shell turreted, spure moderately elevated, apex acute, whorls narrow, carinated at their 
posterior margin; carina rounded; cost longitudinal, straight, or shghtly curved; last 
whorl elongated ; aperture narrow. Axis 2 lines. 
Locality. This pretty minute species is usually found in the soft shelly Oolite beneath 
the planking of Michinhampton Common. — It is somewhat rare. 
Famnily—N aTiciD&. 
Natica, Adanson. 1757. Lam. 
The species of WVatica in the Great Oolite are divisible into two groups; one the 
Natica proper, the others we have arranged in the sub-group Huspira, a name suggested by 
Agassiz, for those species which have the spire more or less elevated, and the volutions 
distinct. 
The Natice, though consisting of a considerable number of species, have, with one 
exception, furnished but a small number of individuals; and those belonging to the sub- 
group Huspira are all rare in the Great Oolite. 
