TROCHUS. 383 



body- whorl these spirals are four in number. Base flat, with a crenulated margin 

 and delicate spiral ornamentation (rarely preserved). 



Relations and Distribution. — The Inferior Oolite variety is more perfectly 

 conical and wider than the Minchinhampton one. Obviously related to 

 T. squamosior, this species never exhibits the deflected basal periphery. 



Rare in the Oolite Marl horizon near Nails worth. 



321. Trochus vicinus, sp. nov. Plate XXXII, fig. 9. 



Description : 



Height . . . . .8 mm. 



Width . . . . .7 mm. 



Spiral angle ..... 57°. 



Shell regularly conical, imperforate. Spire acute and nearly two-thirds of the 

 total height. Number of whorls seven, flat ; those near the apex probably plain ; 

 sutures distinct. Anterior whorls of the spire ornamented with four granular 

 spirals, the posterior of which contains the strongest nodulations. 



In the body-whorl the first and third spirals contain the largest nodulations ; 

 the fourth spiral is often split, and the basal periphery is prominent. Base 

 moderately flat and smooth. Aperture subquadrate with a columellar furrow. 



Relations and Distribution. — In spiral angle and general outline this species 

 greatly resembles T. monilitectus, from which it is chiefly distinguished by its more 

 varied spiral ornamentation, and by a fuller base and less depressed aperture. I 

 have not been able actually to identify this form with any from the Lower Oolites of 

 the east of France, although it seems to run into forms not very unlike Trochus 

 Bellona, d'Orb. 



Common in the Lincolnshire Limestone at Weldon, where the varieties are 

 numerous ; occasionally met with in the Parkinsoni-zone of the Cotteswolds. 



322. Trochus Dunkeri, Morris and Lycett, 1851, var. Weldonis. Plate XXXII, 



fig. 10. 



1851. Trochus Dttnkeri, Morris and Lycett. Great Ool. Moll., pt. 1, p. 61, 



pi. x, fig. 3. 



Description : 



Height and width about . . .7 mm. 



Spiral angle ..... 57°. 



