530 PLIOCENE MOLLUSCA. 



Var. cragtrevelyana, Sacco. Plate XLIX, jfig. 3. 



1848. Scalaria Trevelyana, S. V. Wood, Mou. Crag Moll., pt. i, p. 94, yl. viii, fig. 20. 

 1891. Scalaria (Fnscoscala) Trevelyana, var. cracjtrevelyana , Sacco, Moll. Terr. Terz. Piem , pt. ix, 

 p. 19. 



Varietal Characters. — Smaller and more fragile than the type, with finer and 

 more numerous costse. 



Dimensions. — L. 10 mm. B. 4 mm. 



Distribution. — Not recorded living. 



Fossil : Newbournian Crag : Sutton. Icenian : Bramerton. 



B.eniarJis. — Accepting the view of Prof. Sacco and M. de Boury that the 

 specimen figured by Wood in 1848 as S. Trevelyana should be regarded, not as the 

 typical form, but as a variety of that species, I figure one from the Sedgwick 

 Museum at Cambridge, which M. de Boury considered to be the same. 



Scala (Spiniscala) aldebiana (Sacco). Plate XLVIII, fig. 31 ; PI. XLIX, fig. 1. 



1870. Scalaria Trevelyana, S. V. Wood and F. W. Hariuer, Re^). Brit. Assoc. (Liverpool), p. 90. 



1872. Scalaria Trevelyana, S. V. Wood, Mou. Crag Moll, 1st Suppl., pt. i, p. 58, pi. iv, fig. 6. 



1872. Scalaria Trevelyana, A. and R. Bell, Proc. Geol. Assoc, vol. ii, pp. 214, 216. 



1874. Scalaria TrevelUanum, Van den Broeck, Ann. Soc. malac. Belg., vol. ix, p. 292. 



1879. Scalaria Trevelyana, J. Reeve, Proc. Norwich Greol. Soc, vol. i, p. 79. 



1891. Scalaria (Fuscoscala) Trevelyana, var. aldebiana, Sacco, Moll. Terr. Terz. Piem., pt. ix, p. 21. 



1912. Scalaria Trevelyana, Tesch, Med. v. d. Rijks. v. Delfstoffeu, No. 4, p. 70, no. 161. 



1918. Scala (Spiniscala) aldebiana, de Boury MS. 



Specific Characters. — Shell allied to H. Trevelyana, but much smaller; whorls 

 convex, rounded ; spire short ; suture deep ; base enlarged ; mouth subcircular ; 

 umbilicus and basal ridge wanting. 



Dimensions. — L. 5 mm. B. 3 mm. 



Distribution. — Not recorded living. 



Fossil : Icenian Crag — Norwich zone : Bramerton, Aldeby, 

 Beccles, Yarn Hill, Easton Bavent. Wey bourne zone : Wey bourne. Middle 

 Glacial Sands : Billockby. 



Scaldisien : Belgium, Holland. 



Remarlcs. — The shell described under this name differs essentially both from 

 the recent 8. Trevelyana of British seas and from Wood's Sutton fossil, described 

 in the last paragraph. It was originally based on an imperfect specimen obtained 

 from the Icenian Crag of Aldeby by Messrs. Crowfoot and Dowson. I have since 

 found a good many others, some perfect, one of which, from Bramerton, I have 

 here figured. Prof. Sacco, regarding it as allied to 8. Trevelyana, proposed to 

 call it a variety of that species from the locality at which it was first noticed, 

 but M. de Boury, agreeing that it is not the typical 8. Trevelyana, preferred to 

 regard the name aldebiana as specific rather than varietal, with which I agree. 

 Comparing my figs. 13, 14 and 31 of Plate XLVIII, I think this view will seem not 



