GASTEROPODA. 95 



Whorls 7 or 8, each with a prominent keel forming its anterior 

 margin; sutures deep and angular. Between the keel and the 

 suture the whorls are ornamented with two or four tuberculated 

 secondary ridges, the two median ones being strongest and most 

 constant. 



Base ornamented with spiral striations, of which the strongest 

 are next the border-keel. 



Mouth triangular, slightly effuse below. 



Only a single specimen is known, in the cabinet of Mr J. F. 

 Walker, M.A., and this is not sufficiently well preserved to serve 

 for perfect specific diagnosis. 



Measurements. Height, 12 mm. ; breadth, 13 mm, ; apicial 

 angle, 80". 



Locality. Upware (Collection Mr J. F. Walker, M.A.). 



LiTTORINA, sp. 



Nearly allied to L. JJ pwarensis, h\ii much shorter, being nearly 

 as broad as long. 



Locality. Upware (Woodw. Mus., unique). 



LiTTORINA Upwarensis, sp. nov. 

 (Plate III., fig. 10, a, h.) 



Shell thick, pyramidal, with oblique base, longer than broad, 

 ornamented with tuberculated spiral ridges. Sutures deep ; whorls 

 6 or 7, convex, ornamented with two tuberculated keels, of which 

 the more posterior is the stronger and more coarsely nodulated. 

 This keel occupies the centre line of each whorl in the spire. 

 Posterior to this the whorls are usually slightly concave, and 

 plain, but an additional ridge, with tubercles, may be developed 

 along the sutural border. 



The body-whorl has numerous (9 or 10) spiral ridges upon its 

 sides and base, the posterior two or three being distinctly tubercu- 

 lated, the remainder less so. 



The base is convex and oblique. 



Mouth rhomboidal ; the columellar lip slightly produced. 



b 



