372 GASTEROPODA OF THE INFERIOR OOLITE. 



The small variety figured in the accompanying plate is characteristic of the 

 Opalinus-zone of Drympton and Haselbury, and probably of other localities. Some 

 specimens more conical than the one figured I distinguish in my collection as var. 

 conica. There is also a large variety in the Murchisonse-zone of Burton Bradstock 

 which comes very near to T. Sedgwickii, Munst. It is just possible that a modifi- 

 cation of this species — or species-group — from the Dogger is represented in ' Geol. 

 Mag.,' 1885, pi. ii, fig. 13. 



309. Teochus Winwoodi, Tcwtmey, 1873. Plate XXXI, fig. 4 (minor), fig. 5 (major). 

 1873. Teochus "Winwoodi, Tawney. Dundry Gasteropoda, p. 34 (26), pi. ii, fig. 8. 



Bibliography, Sfc. — This species was based upon a single specimen in the 

 Bristol Museum, the locality being uncertain. The author observed that there 

 was some resemblance to Quenstedt's figure of Trochus bijugatus (' Der Jura,' p. 

 485, pi. lxv, fig. 9). Since the year 1873, analogous if not positively identical 

 forms have been found abundantly in the Concavus-bed at Bradford Abbas, where 

 the species exhibits great variety. The form is probably derived from the more 

 conical varieties of the Sandersii-growp, which is, in the main, characteristic of a 

 lower horizon. 



Description, var. minor : 



Height . . . . .19 mm. 



Basal width . . . . .15 mm. 



Spiral angle ..... 47° 



Shell regularly conical, elevated, more or less umbilicated. Spire acute and 

 occupying nearly two-thirds of the entire height. Number of whorls seven or 

 eight ; these are concave with finely tuberculated keels, not very salient, at the 

 posterior and anterior margins, the intervening space being seamed with 

 granulated spiral striae somewhat decussated axially ; sutures wide and regular. 



The body-whorl is similar in shape and similarly ornamented, the second 

 carina forming the angle of the whorl, immediately below which, and partly in the 

 base, is a third subordinate carina. The base inclines to be flat, though rising 

 anteriorly, and is richly ornamented with granular spirals which are partly 

 decussated by axial striae and growth-lines : a row of slight tubercles girdles the 

 umbilicus, which is sometimes barely indicated. Aperture trapezoidal. 



In the variety major the ornaments are much coarser, in the whorls of the 

 spire a third carina being exposed. In the body-whorl this attains to considerable 

 importance, so as to produce a duplicate keel at the angle of the shell. The 



