46 R. BULLEN NEWTON on 



surface spirally ridged, an outer pair of ridges being prominent, well separated, 

 and parallel to each other ; posterior surface of whorls decorated with a pair 

 of distant, finely-beaded circlets. 



DIMENSIONS. 



Alt. (approximate) ... ... ... 65 millimetres. 



Lat. ... ... ... ... 29 



REMARKS. There are only three specimens to illustrate this species and 

 these unfortunately have imperfect terminations with consequently fractured 

 apertures. The spires, also, have been very much smoothed by erosion, 

 although this is interesting as tending to prove an estuarine origin for the 

 deposits. The species is undoubtedly related to Cerithium angulosum of 

 Lamarck, from the European Eocene, which Cossmann has selected 

 as the type of his genus Execkestoma. 1 It chiefly differs, however, in its 

 flatter and more expansive base, besides having more prominent peripheral 

 tubercles, as well as possessing the pair of beaded circlets on the posterior 

 surface of the whorls without any further spiral ornamentation, besides being 

 furnished with a pair of spiral ridges which are just within the outer margin 

 of the basal region. Execkestoma is grouped with Potamides forms of the 

 Cerithiidae as well as being closely related to De Montfort's genus Pyrazns 

 of which the type is Cerithium ebeninum of Bruguiere belonging to Recent 

 seas, a genus, however, which has a more elongate aperture and a columella 

 of deeper excavation. 



The specific name is in honour of Monsieur Maurice Cossmann, the 

 distinguished palaeoconchologist of Paris. 



OCCURRENCE. Cutting No. 6. 

 COLLECTOR. Mr. Kitson. 



Terebralia, sp. A. 

 PLATE 4, fig. 10. 



DESCRIPTION. This specimen, deficient in the apical region, is elongately 

 conical, and composed of nearly six whorls of which the last is about double 

 the height of the penultimate and furnished with a rounded and inflated 



1 Cossmann: Ann. Soc. R. Mai. Belgique, 1889, Vol. 24, p. 71, and Essais de Pala^oconchologie 

 Compares, 1906, part 7, p. in. 



