ALARIA. 135 
54, Atarta Lortert, D’Orb., var. gracilis, Lycett, 1853. Plate VI, fig. 5. 
1853. Rosrentarta eractiis, Lycett. Proc. Cotteswold Nat. Field Club, vol. i, 
p- 80. 
Description.—* Spire lengthened, smooth. Whorls six, lengthened, angulated, 
the angle being in the middle of the whorl, forming an acute and crenulated 
carina; body-whorl smooth, with two carine and large digital processes; caudal 
extremity slender and lengthened. The slender form, crenulated carina, and 
smooth surface distinguish it from R. trifida.”—Lycerrr. 
The figured specimen, which is believed to be Lycett’s type, presents no 
crenulations other than the result of usage, and this is also the cause of the 
smoothness, the spiral lines having been rubbed down almost to obliteration. The 
appearance of smoothness in fossils obtained from oolitic freestones is in most 
cases merely due to rolling. The ‘caudal extremity ” is not particularly lengthened, 
and there are indications in the specimen of the commencement of the hamicaudal 
curve. The mean spiral angle is about 28°. 
Relations and Distribution.—This variety is more slender than the majority 
of the specimens referred to Al. Lorieri from the Parkinsoni-zone of Burton 
Bradstock. It may, in fact, represent the typical Al. Lorieri of D’Orbigny. 
There is a particular interest attaching to the figured specimen, viz. that it 
is the earliest recorded example of the trifida-group in this country. It was 
obtained from the Freestones below the Oolite-Marl near Leckhampton, which are 
well within the Murchisone-zone. Such fossils must be extremely rare, since no 
species of the trifida-group is quoted from any horizon of the Inferior Oolite in 
Witchell’s ‘ Geology of Stroud.’ Since the few species of Alarie hitherto discovered 
in the British Lias appear to belong to the Monodactyl section, this is the earliest 
Didactyl Alaria known in this country. 
55. ALARIA PONTONIS, sp. nov. Plate VII, figs. 1 a, 1b, and var. spinifera, Plate 
VII, fig. 2. 
Description : 
Length : 2 : : . 22mm. 
Width of body-whorl to height of shell . 50:100 
Spiral angle . : : ; . 42° 
