JF. H. Eudleston—The Yorkshire Oolite. 127 



beai' some resemblance to the specimen under consideration. The 

 proportions of B. Dyonisea especially come very near, but the lines 

 of growth are represented as being fine in that species. 



Genus Action, Montfort, 1870 = Tomatella, Lamarck. 



Shell conically ovate, with a conical, many-whorled spii'e. 

 Spirally grooved or punctate-striate ; columella with a long tortuous 

 fold. 



AcTiEONiNA, D'Orbigny, 1850, is an Acfceon [Tomatella), without 

 plaits on the columella. Cylindrites, Lycett, 1850, is regarded by 

 S. P. Woodward as a subgenus of Actceon (cf. Great Ool. Moll. p. 97, 

 and Manual of Mollusca, p. 180). Section 1 : Shell smooth, slender, 

 subcylindrical ; spire small, aperture long and narrow, columella 

 rounded, twisted and directed slightly outwards. Section 2 : Shell 

 oval, spire sunk, whorls with acute margins. This subgenus is 

 apparently not recognized by continental authors. 



56. — AcTiGON RETusus, Phillips, 1829. Plate IV. Fig. 7. 

 Actceon retusiis, D'Orbigny. Prod, de Pal. Strat. vol. i. p. 353, Et. Oxf. 

 Bibliogrnphi/, e^c — Phillips's specimen most probably came from 

 the Lower Calcareous Grit of the coast. The columella in his 

 figure appears more twisted than is the case with the specimen 

 under consideration. 



Description. — Specimen from the Coral Eag of Ayton (Leckenby 

 Collection). 



Length 19 millimetres. 



"Width .. 9 „ 



Ratio of body-whorl to entire length 76: 100. 



Shell ovately-cylindrical, smooth. Spire composed of four or five 

 whorls, which are tumid, increase suddenly, and are clearly separated 

 by the suture. The height of the body- whorl is three-fourths of the 

 entire shell. In form it is an ovate cylinder rapidly contracting at 

 either extremity. The aperture extends over almost the entire 

 length of the body-whorl, and is narrow posteriorly. The outer lip 

 appears to be rather thick. The inner lip, nearly straight at first, 

 is strongly excavated anteriorly, but scarcely twisted (? Actceonina) . 

 It projects clear of the columella, Avhich is solid. Anterior portion 

 of the aperture wide. No markings other than fine lines of growth 

 can be distinguished. 



Relations and Distribution. — This form is near to Bulla {Actaionina) 

 oUvceformis, Koch and Dunker (Nordd. Oolith. p. 41, pi. v, fig. 3), 

 which is said to occur in the Upper " Coral 1 en kalke " of the Middle 

 Oolite along with Astarte rotundata, Eoemer, Melania striata, 

 Sow., and Cidarites Blumenbachii, Goldf. — the very species which 

 are companions of the Ayton shell. Phillips's species is more usually 

 met with in the Lower Calcareous Grit, but it is not common any- 

 where. 



57. — Cylindrites elongatus, Phillips, 1829. Plate IV. Fig. 8. 



Bulla elongala, Phillips, 1829, Geology of Yorkshu'e, vol. i. pi. iv. fig. 7. 

 Cylindrites elongata, Phillips, 1875, oj). cit. 3rd ed. p. 260. 



