ACTAONINA. 473 
Shell oval-elongate. Total number of whorls six, the spire occupying from 
three to four tenths of the entire height. The apex is slightly obtuse. The 
whorls are subconvex, with a narrow posterior ledge indented by a deep groove ; 
sutural angle oblique. The body-whorl is very ovate, and like the rest of the 
shell perfectly smooth, growth-lines alone being visible. The aperture is oval- 
elongate, and about half the height of the entire shell. There is a considerable 
incrustation on the columella, which is only shghtly sinuous. 
Relations and Distribution—The peculiar ovate-elongate character of this shell 
and the convexity of the whorls forcibly remind us of Acteonina Loriereana, @Orb., 
which may be regarded as a typical Ovactxonina. On the other hand, the grooved 
ledge on the posterior margin of the whorls, although very narrow, serves to 
remind us of Striactxonina. 
A single specimen from the Concavus-bed, Bradford Abbas. 
420. AcTHONINA (CYLINDROBULLINA) GLABRA, Phillips, 1829. Plate XLII, figs. 22, 
23 a, 23 D. 
1829-35. Actrmon @LABER (Bean, MS.), Phillips. Geol. Yorks., part 1, pl. ix, fig. 31. 
1851. Acrmonina GLaBRa, Phillips. Morris and Lycett, Grt. Ool. Moll., part 1, 
p- 120, pl. xv, fig. 10. 
1885 PRP — — -- Hudleston, Geol. Mag., 1885, p. 205, pl. v, 
figs. 6 and Ga. 
Bibliography, Se.—The type of Actxon glaber is probably lost, but figs. 23a, 
23 b represent a specimen in the Bean Collection (that portion now in the British 
Museum), which is thus labelled. Although a typical form, it is somewhat larger 
than usual, and the drawing suggests Cylindrites, for which there is probably no 
justification. Fig. 22 represents a medium-sized shell. 
Description : 
Height . 5 . 10—20 mm. 
Body-whorl to total Roehe.. ; SO KOO 
Spiral angle : 5 ash 
Shell cylindro-conical, with a very Sitort spire. ‘lhe whorls of the spire (four) 
are sub-tumid and sloping with a posterior ledge or tabulation which is rounded 
off at the margin. The body-whorl is elongate and quite cylindrical, and like the 
rest of the shell smooth, even the growth lines being very fine, and in many 
specimens scarcely visible. 
The aperture is extremely long and narrow in the upper half, but widens 
anteriorly owing to the hollowing out of the columellar region; the columellar 
