LITTORINA HEADLEYI. 665 



Specific Characters. — Shell minute, ovate; whorls 5, convex, the last ventricose, 

 much the largest, three-fourths the total length, angulated at the periphery, 

 showing oblique lines of growth, but otherwise without sculpture; spire conical, 

 very short and small, with a compressed apex; suture fairly deep and channelled; 

 mouth large, sub-ovate; outer lip compressed, sharply inflected above; inner lip 

 covering the pillar, gradually becoming wider, reflected and expanded below. 



Dimensions. — L. 3'5 mm. B. 25 mm. 



Distribution.- — Not known living. 



Fossil: St. Erth. Walton i an Crag : Little Oakley. 



Remarks. — The fossil here figured under Mr. Bell's name is the specimen he 

 obtained some years ago at St. Erth. We are unable to refer it satisfactorily to 

 any species known to us. It is from the Warburton Collection at the British 

 Museum. Another was found by Mr. Bell at Oakley. 



Littorina Headleyi, A. Bell. Plate LIII, fig. 14. 



1884. Littorina (?) globosa, Jeffreys, Quart. Journ. G-eol. Soc, vol. xl, p. 320, pi. xv, fig. 1. 

 1919. Littorina Headleyi, A. Bell, Yorks. Naturalist, p. 58. 



Specific Characters. — Shell minute, rather thick, opaque ; whorls 4, convex, 

 without ornament, the last much the largest; spire short, regularly diminishing to 

 a blunt point ; suture slight ; mouth angulate above, rounded below ; pillar broad, 

 thickened at the base, with a small umbilical chink behind it. 



Dimensions. — L. 2-5 mm. B. 2'25 mm. 



Distribution. — Not known living. 



Fossil: Pleistocene: Bridlington. 



Remarks. — The shell here represented is from the Headley Collection, where 

 it bears Jeffreys' original name of L. globosa. As that had been previously used 

 by him for a variety of L. nulls, Mr. Bell has suggested for it the term Headleyi, 

 in which I follow him. Jeffreys states that about six specimens had been 

 obtained at Bridlington, all so imperfect that he was doubtful as to whether they 

 belonged to Littorina or Trochus. Neither his figure nor that here given seems to 

 represent exactly the fossil. There is often much difficulty in getting accurate 

 enlargements of these minute forms. 



Genus LACUNA, Turton, 1827. 

 Lacuna pallidula (Da Costa). Plate LIII, fig. 25. 



1778. Nerita pallidula, Da Costa, Brit. Couch., p. 51, pi. iv, figs. 4, 5. 



1804. Nerita pallidula, Donovan, Brit. Shells, vol. i, pi. xvi, fig. 1. 



1819. Turbo pallidulus, Turton, Conch. Diet., p. 192, pi. xxv, figs. 85, 86. 



1853. Lacuna pallidula, Forbes and Hanley, Brit. Moll., vol. iii, p. 56, pi. lxxii, figs. 1, 2. 



