ACTiEONINA. 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 slightly sinuous. 



Belations and Distribution. — The peculiar ovate-elongate character of this shell 

 and the convexity of the whorls forcibly remind us of Adseonina Loriereana, d'Orb., 

 which may be regarded as a typical Ouacixonina. On the other hand, the grooved 

 ledge on the posterior margin of the whorls, although very narrow, serves to 

 remind us of Striactaeonina. 



A single specimen from the Concavus-loed, Bradford Abbas. 



420. AcT^oNiNA (Cylindrobullina) glabra, Phillips^ 1829. Plate XLII, figs. 22, 



23 «, 23 h. 



1829-35. AcT.^ON glabee (Bean, MS.), Phillips. G-eol. Torks., part 1, pi. ix, fig. 31. 

 1851. AcT^ioNiNA GLABRA, PliHUps. Moms and Lycett, Grt. Ool. Moll., part 1, 



p. 120, pi. XV, fig. 10. 

 1885 ? — — — HudlestoD, Geo!. Mag., 1885, p. 205, pi. v, 



figs. 6 and 6 a. 



Bibliography, 8fc. — The type of Adseon glaber is probably lost, but figs. 23 a, 

 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 Cylinclrites, for which there is probably no 

 justification. Fig. 22 re|)resents a medium-sized shell. 



Description : 



Height ..... 10—20 mm. 

 Body- whorl to total height . . . 90 : 100. 



Spiral angle .... 80°. 



Shell cylindro-conical, with a very short spire. The 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 



