CERITHIUM. 157 



77. Cerithium leokhamptonense, sp. nov. Plate IX, fig. 2. 



Description : 



Length (about) . . . .27 mm. 



Width . . . . .9 mm. 



Length of body-whorl to entire shell about . 33 : 100. 



Spiral angle .... 20°. 



Shell elongate, scarcely turrited ; number of whorls probably twelve, apical con- 

 ditions unknown. Whorls short, slightly convex in the middle stage, but becoming 

 flat anteriorly, sutures close. The ornaments consist of about ten spiral lines of 

 somewhat unequal strength, which are decussated by numerous thick, though not 

 prominent costas, which are slightly arcuate, and slope considerably from left to 

 right. The costse become faint in the penult. 



The body-whorl is about one-third the total length of the shell. Fine spiral 

 lines are the only ornaments, the costse having entirely disappeared. Base tolerably 

 full and spirally striated. Aperture (?) ovate, with a considerable callus on the 

 columella. Other indications wanting. 



Relations and Distribution. — As far as I know, this form seems to stand pretty 

 much by itself. The failure of axial costae on the anterior whorls might suggest 

 some degree of relationship to certain varieties of the vetusturn-growp, but otherwise 

 there is no resemblance. 



A single specimen from the Inferior Oolite of Leckhampton Hill. 



78. Cerithium (species or variety). Plate IX, fig. 3. 



Description : 



Length (about) . . . .20 mm. 



Width . . . . .4 mm. 



Spiral angle (about) . . . 10°. 



Shell very subulate, turrited ; spiral angle nearly regular. Whorls about sixteen, 

 short and very flat; suture close. The extreme apical whorls are apparently 

 devoid of ornament. The subapicals have three well-cut spirals, which decussate 

 with numerous longitudinals of about equal strength, inclining from left to right. 

 Four, and ultimately five, spirals are developed in the anterior whorls. Avery fine 

 mesh results from the decussation of such equal spiral and longitudinal lines, the 

 enclosed space being rectangular and spirally elongated ; the nodes at the inter- 

 sections are very slight. 



