FAUNA OF THE CORNBRASH. 



Bittium lorieri (Heb. and Desk). Plate VII, fig. 11. 



1860. Cerithiwm lorieri, Hebert and Deslongehamps, Bull. Soc. Linn. Normand., vol. v, p. 192, 



pi. vi, fig. 2. 

 1884. Cerithium muricatum, Hudleston, Geol. Mag. [3], vol. i, p. 54, pi. iii, fig. 4. 



Description. — Our specimens agree in all respects with the type : the length 

 is 21 mm. ; greatest breadth, 6 mm. ; spiral angle, 10°. There are sixteen whorls, 

 including the apex. The general level of the sides of the spire is almost uniform, 

 so that there are steps at the sutures. The longitudinal ribs are 21 per whorl, 

 and are closer together than the spiral ones. They decrease in height, and die out 

 anteriorly. The knobs are much raised but rounded at the top. On the base are 

 seven raised spirals, decreasing anteriorly. The most posterior one is crimped 

 posteriorly by the longitudinal raised line. 



Distribution. — Two exceedingly characteristic specimens have occurred at 

 Shipton-on-Cherwell. More imperfect forms have been found at Thrapston (1), 

 at Scarborough (7, including the specimen figured by Hudleston), and at Bedford 

 (1). The species occurs also at Le Waast in the Boulonnais. 



Relations. — In these small Bittia, unless the characters are very closely noted, 

 it is impossible to say how far agreement may be recognised with other forms. 

 This is a finer shell than B. pingue, and has 4 knobs in a longitudinal group 

 instead of 5, and 21 groups in the last whorl instead of 24, so that the knobs are 

 less crowded together. It is quite possible such changes might take place in a 

 single shell, but they have not been seen to do so. With regard to G. muricatum, 

 if we define it as having " 5 (or 4) rows of knobs arranged in straight (or curved) 

 longitudinal bands," our shell may be included therein, but not if we leave out the 

 brackets. The same is the case with G. russiense of D'Orbigny and C. granulato- 

 costatum of Goldfuss. 



Genus CRYPTAULAX, Tate. 



The following is the author's definition : " Shell turriculated, pointed, with a 

 polygonal spire ornamented with transverse costae, angles of whorls disposed in a 

 more or less marked spiral series ; imperforate columella straight, thin, aperture 

 ovate, not produced into a distinct canal in frout, peristome entire, broadly reflexed 

 upon the left lip, a shallow oblique posterior canal in the angle formed by the body 

 whorl and outer lip." 



