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 Al. 



ALIEN1GENA. 



43. Alaria Dundryensis, Tawney, 1873. PI. V, fig. 2. Type refigured. 



1873. Alaeia Dundryensis, Tawney. Dundry Gasteropoda, p. 12, pi. 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 

 costse in the [anterior] whorls, *. e. the last, but are vertically compressed ; the 

 surface shows faint [longitudinal] lines ; there are fine [spiral] lines, which are 

 stronger near the suture." — Tawney. 



Description : 



Length . . . . .30 mm. 



Width of body- whorl to height of shell . . 44 : 100. 



Spiral angle . . . . .36°. 



The type is one of those shells preserved in crystalline calcite, where the orna- 

 mentation has probably undergone considerable modification, and this especially 

 affects the length of the costse. The body- whorl is almost unicarinate and without 

 costas ; 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 ; it is 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. Boubaleti, 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. 



