SCALA (CLATHRUS) COMMUNIS. 535 



Pleistocene : March gravels, Selsey, Torbay, Cliesliire, Stretliill, Lillesliall, 

 Cumbrae, Shewalton. 



Pliocene : Roussillon, Altavilla, Livorno. 



Pleistocene : Sicily — Messina, Ficarazzi, Monte Pellogrino, Catania, Castrorcale. 

 Calabria — Reggio, Gravina. Cliristiania — Taj)es-hixnks. 



Bemarls. — The sub-g'enus Gldtltnis, of which the present species is taken as the 

 type, includes a group of imperforate Scalas, solid, conical and turreted, with 

 smooth, convex, disjoined whorls, and lamelliform costas, cemented at the suture 

 and having a rounded base. 



8. coiiimunis has rather a wide range as a recent shell, but as a fossil seems 

 characteristic of Pleistocene rather than of Pliocene deposits. It has been but 

 rarely recorded from the English Crag, but is reported by Prof. Br/argger from the 

 Pleistocene IVipes-banks of the Cliristiania fiord, and by Seguenza from a number 

 of Sicilian and Calabrian localities. Dr. Scalia has found it in the comparatively 

 recent sub-Etnaen beds of the Catania region, as I have done in the March gravels 

 and Mr. Bell at Selsey and elsewhere. 



In the Min. Conch., vol. i, p. 4<9, Sowerby, referring to another Crag species 

 of Scala, remarks that specimens of it are generally so brittle that they are apt to 

 fall to pieces. My own experience is similar as to those found in the Red Crag ^ : 

 out of a hundred in my collection from Oakley almost all are imperfect, owing 

 probably to the disjoined character of the whorls, many of them being composed 

 of a single whorl only. In the Icenian or Norwich Crag, on the contrary, complete 

 examples of Scala, most frequently those of 8. grwulandica, a non-disjoined species, 

 are the rule rather than the exception. It is possible, therefore, that in the Red 

 Crag some species of Scala may have been more common than we have been 

 accustomed to suppose, fragmentary specimens of them having been passed over 

 by collectors without notice. The importance of preserving imperfect specimens 

 when collecting, for subsequent and more careful examination, cannot be too 

 strongly insisted on. As far as the present species is concerned, M. de Boury 

 recognised among some broken fragments of Scala from Oakley, hardly good enough 

 to figure, one or two which he considered the true 8. communis. 



I am figuring a recent specimen of S. communis for purposes of comparison, 

 together with another from the York Museum, which was found at Waldringfield 

 and has been identified with it.^ 



1 Perfect specimens are more frequently met with in the Coralline Crag, the molluscan fauna of 

 which was evidently accumulated under different conditions. 



" M. de Boiu-y doubted whether this identification was correct. I suggest, however, that the latter 

 specimen may probably represent a Crag form of the present species. 



