480 GASTEROPODA OF THE INFERIOR OOLITE. 



Bibliography, Sfc. — The type is preserved in the Jermyn Street Museum. It 

 cannot be said to correspond very closely with Lycett's diagnosis. 



Description. — (Based upon the specimen in the Jermyn Street Museum.) 

 Height 17 mm., width 9 mm. Shell cylindrical, but tapering anteriorly. The 

 spire, consisting of about five whorls, is nearly flat and slightly sunken, but with a 

 prominent mammilliform apex of considerable size. The posterior margin of the 

 body-whorl is flattened and encloses the spire, the dividing suture lying in a deep 

 groove. The columellar lip is strongly twisted. 



The var. Weldonis is a fossil of much smaller habit, the usual height being 

 8 mm., width 4 mm. It is also somewhat more pyriform in figure. 



Relations and Dlstributio)i. — Belongs to the section of Ci/lindrites which have 

 sunken spires. Difi'ers from Cy. mammlllaris in the extensive flattening of the 

 posterior margin of the body-whorl, and in the groove which divides this from 

 the spire-whorls ; it is also rather broader in proportion to its length. 



The specimen in the Jermyn Street Museum, from the Inferior Oolite of 

 Nails worth, is the only one I have seen from the Cottes wolds. The var. Weldonis 

 is the most abundant Cylindrite in the Lincolnshire Limestone at Weldon and 

 Ponton. 



432. Cylindrites mammillaeis, Lycett, 1850 (not figured). 



1850. Cyltndeites mamillaris, Lycett. Ann. Mag. Nat. Hist., 2nd ser., vol. vi, 



p. 418. 

 1853. — — — Proc. Cotteswold Nat. Club, vol. i, 



p. 79. 



Description. — Height 20 mm., width 8 mm. in a good-sized specimen. Shell 

 cylindrical, elongate, sharply truncated atop. Spire flattened and sub-depressed, 

 but the inner whorls have their upper flat surfaces visible, the first two or three 

 of which are rounded into a mammillary knob. Aperture elongate with a strong 

 columellar fold. 



Relations and Distribution. — This is an extremely narrow and cylindrical form, 

 only differing from Cy. cyliiidricus, Morris and Lycett, in the salience of the 

 mammillary knob and in the flattening, rather than depression, of the spire. 



There are two specimens of Cy. mammillaris in the Brodie Collection from the 

 Leckhampton Freestones. A variety, approaching Gy. cyliiidricus, also occurs 

 sparingly in the Lincolnshire Limestone of "Weldon. This has been quoted as 

 Cy. cylindricus. 



