GASTEROPODA. 21 
the opposite side of the whorl is another distinctive character. ‘The caudal extremity is 
short and straight. Length, 10 lines; breadth, including digitations, 9 lines. 
Locality. his species is found in all the shelly beds, but is far from common. 
Auaria teiripa, Phil. sp. Plate TI, figs. 11, lla, 114, lle. 
RostELnarta TRIFIDA, Phillips. 1835. Geol. of Yorksh., i, t. 5, fig. 4. 
— BISPINosA, Phillips. Geol. of Yorksh., i, t. 4, fig. 32. 
= BICARINATA, Goldfuss. Petref, t. 170, fig. 1. 
— rrirmpa, Deslongchamps. Mém. Soc. Linn. Normandie, vol. vii, pl. 9, 
figs. 28, 29, 30, 31. 
— — Desh. Uam. An. sans Vert., 2d Edit., t. 9, p. 665. 
A. “ Testd fusiformi, turritd, transverse striatd, anfractibus medio carinato-acutis ; ultimo 
bicarinato, gibbo ; ald didactyla, digitis in etate adultd longissimis, recurvatis ; in juniore 
modo unico, modo duobus inequalibus digitis, seu inferiore, seu superiore longiore ; caudd 
longissimd, recurvatd ; apertura angustatd.” (Deslongchamps.) 
Shell fusiform turreted, transversely striated ; whorls acutely carimated about the middle 
part ; the last whorl has two carine, the upper of which is most prominent, and has a 
prominence or spine opposite to the aperture. The wing is digitated; when full grown 
the digitations are very long and recurved, the larger being sometimes the upper, and at 
other times the lower digitation. In the young state it has only one carina and digitation. 
The canal is very long and recurved, the aperture small. 
Having had the advantage of examining a large number of specimens, comprising every 
variety both in form and stage of growth, we feel no hesitation in uniting the two species 
here indicated. The whorls have every degree of angularity, specimens of 4. dispinosa 
having the lower half of each volution simply cylindrical, the carina not projecting beyond 
it, and the first three or four whorls are smooth and simply convex, scarcely showing any 
trace of angularity. The extreme of the other variety has the carina not only angulated 
acutely, but spread out horizontally into a prominent tabular border. 
The encircling striz are equally variable. In some instances the striz are regular and 
equal, but more frequently they are alternately large and small; at other times, however, 
they are altogether irregular and unequal. 
Locality. This species occurs throughout the whole of the Great Oolite near Minchin- 
hampton ; even the upper beds, when shelly, not unfrequently contain it. Undoubtedly it 
is the most common example of the genus. In the Calcareous grit; Oxford Clay; Kelloway 
Rock, near Scarborough, Yorkshire (Pdz//ips). 
M. E. Deslongchamps describes this species as occurring throughout the jurassic series 
of Normandy, viz. the Zias, Fontaime-Etoupefour ; Inferior Oolite, Bayeux; Great Oolite, 
Ranville; Oxford Clay, Vaches-Noires ; Kimmeridge Clay, Villerville. 
A 
