284: GASTEROPODA OF THE INFERIOR OOLITE. 
can be traced are anteriorly bicarinate; in the next stage a posterior spiral is 
further developed; later still there are four spirals, of which the third forms the 
most salient carina; the spirals are more or less tuberculate ; in the interspaces 
subordinate spirals may be detected. 
The ornamentation of the body-whorl is very elaborate. There are five 
primary spirals, the fourth being the most salient, and constituting with the fifth 
a double carination. In the posterior spiral the nodules are nearly circular, the 
other spirals are serrated; there are about half a dozen deeply-serrated spirals in 
the base ; the interspaces throughout are cross-hatched with coarse axial lines. 
The aperture is ovate-elongate in the earlier stages, with a certain amount of 
anterior canaliculation, but becomes more round in the larger shells, as is usually 
the case with Amberleya. 
Relations and Distribution —This might almost be called Amb. Meriani, Goldf., 
var. major. The ornamentation, as shown in the enlargement of that author’s 
figures, greatly resembles the ornaments of Aimb. cygnea. But ours is a finer and 
more eucycloid form, which possesses peculiarities worthy of distinction. It differs 
still further from d’Orbigny’s Turbo Meriani (T. J. ii, pl. ecexxxvy, figs. 1—5). 
The ‘ Bastard-bed,” in which this handsome member of the ornata-group 
occurs, lies at the base of the Lincolnshire Limestone, and just above the Iron- 
stone at Lincoln. Here Amb. cygnea is fairly plentiful in a rough fawn-coloured 
matrix along with many other interesting Gasteropoda. 
214, Amperteya GontaTa, Deslongchamps, 1860. Plate XXII, fig. 6 (juv.). 
1860. Evcyctus contatus, J. A. Deslongchamps. Bull. Soc. Linn. Norm., 
vol. v, p. 31, sep. copy, pl. xi, fig. 6. 
1873. AMBERLEYA ? GontATA, Des/., sp. Tawney, Dundry Gasteropoda, p. (20) 
28, pl. ii, fig. 5. 
The type occurs in the Inferior Oolite of Les Moutiers. The specimen figured by 
Tawney appears correctly identified with Deslongchamps’ species, which is probably 
only a bizarre variety of the one described on the next page. Fig. 6 most likely 
represents the young stage. This form is found rarely in the Parkinsoni-zone of 
Burton Bradstock. It is more markedly angular and more coarsely ribbed than 
the commoner form next to be described, and has rather a wider spiral angle. All 
members of the goniata-group have a sharp spire with an obtuse apex (see 
enlargements of figs. 6 and 11). 
