122 GASTEROPODA OF THE INFERIOR OOLITE. 
spire and its ornaments. The spire also has many points of resemblance to that 
of Al. fusca, but the digitation is more slender, and less abrupt in its upward 
curve. 
A single specimen from the Inferior Oolite of North Dorset, horizon and 
locality unknown. As a mere name of convenience I would suggest that of At. 
ALIENIGENA. 
43. Atarta Dunpryensis, Tawney, 1873. Pl. V, fig. 2. Type refigured. 
1873. Ataria Dunpryensis, Tawney. Dundry Gasteropoda, p. 12, pl. i, fig. 5. 
Description.—* Shell fusiform, elongate. Whorls seven to nine, angular; 
the keel not quite in the middle of the whorl, but inferior thereto; on the keel is 
a series of tubercles, probably twelve to fourteen on a whorl, which do not form 
coste in the [anterior] whorls, 7.e. the last, but are vertically compressed; the 
surface shows faint [longitudinal] lines; there are fine [spiral] lines, which are 
stronger near the suture.”—Tawnery. 
Description : 
Length - : . 30 mm. 
Width of body-whorl to sheen of shell. . 44: 100, 
Spiral angle . : hon 
The type is one of those shells nrosennede in seratalline calcite, where the orna- 
mentation has probably undergone considerable modification, and this especially 
affects the length of the costae. The body-whorl is almost unicarinate and without 
coste ; no spines are preserved, though there is good reason to suppose that a 
very prominent one existed a quarter of a turn above the wing. The base of the 
wing (which doubtless was monodactyl) is ornamented by fine cross-hatching, and 
it has a slight tendency to overlap the anterior portion of the penultimate. Other 
indications wanting. 
Relations and Distribution—The sub-median position of the keel, and its 
marked prominence, serve to separate this species from all members of the hamus- 
group; itis also much more unicarinate, and probably possessed a digitation of a very 
different character, which may have resembled that of Al. fusca, but which more 
probably resembled that of Al. Roubaleti, var. Dorsetensis, next to be described. 
The type-specimen is from the Inferior Oolite of Dundry, and is the only one 
known to me which presents any describable features. 
