434 PLIOCENE MOLLUSCA. 



generally used by English Conchologists and by the Committee of the Conchological 

 Society of Great Britain. 



Beside the present species, widely diffused and fairly abundant in British seas 

 during the various stages of the Pliocene and Pleistocene epochs, as it is at the 

 present day, and a small form which appears to correspond more or less nearly 

 with a Miocene variety and is described in the next paragraph, I have two different 

 but nearly allied species in my collection from the Antwerp Crag. Possibly these 

 may have been overlooked by English collectors, or, if not, they may turn up at 

 any time. It seems to me desirable, therefore, to figure my Belgian specimens in 

 order to call attention to the subject and to show wherein they differ from the 

 characteristic English form. 



A. pes-pelicani is included by Prof. Bro'gger in the list of Lusitanian shells 

 before referred to, which he finds, mixed with arctic and boreal mollusca, in the 

 later stages of the Pleistocene deposits of the Christiania region. It occurs at 

 many localities of the Sicilian and the English Pleistocene. 



MM. Bucquoy, Dautzenberg and Dollfus suggest that A. pes-pelicani may be a 

 descendant of the Oligocene species A. speciosa, Schlotheim. 



As stated above, most of the Crag specimens of A. pes-pelicani are smaller than 

 the recent British shell, averaging from 25 mm. to 35 mm. in length. These Nyst 

 identified in 1881 (op. cit,, p. 81) with the Chenopus anglicusoi D'Orbigny (op. cit.) ; 

 those figured by Sowerby, Wood and Nyst are of this type. 



Var. minor, Bucquoy, Dautzenberg and Dollfus. Plate XLI, fig. 30. 



1852. Chenopus pes-pelicani. Homes, Foss. Moll. Tert. Wien, vol. i, p. 194, pi. xviii, fig. 4. 

 1881. Chenopus pes-pelicani, Fontannes, Moll, plioc. Vail, du Rhone, vol. i, p. 153, pi. ix, fig. 3. 

 1884. Aporrhais pes-pelicani, var. minor, Bucquoy, Dautzenberg et Dollfus, Moll. mar. Rouss., vol. i, 



p. 220, pi. xxiii, fig. 11. 

 1886. Aporrhais pes-pelicani, var. minor, Dollfus et Dautzenberg, Feuilles des jeunes Nat., vol. xvi, 



p. 105. 

 1893. Chenopus pes-pelicani, Sacco, Moll. Terr. Terz. Piem., pt. xiv, p. 30. 



Varietal Characters. — Much smaller than the type, with shorter wings and spire 

 and finer sculpture. 



Dimensions. — L. 20 mm. 

 Distribution, — Recent : Mediterranean. 



Fossil : Coralline Crag : Boyton. Waltonian : Little Oakley. 

 Probably at other localities in the Crag. 

 Miocene : Touraine, Vienna basin, Italy. 

 Lower Pliocene : Italy, Rhone valley. 

 Upper Pliocene: Italy (Astigiauo). 



