528 PLIOCENE MOLLUSCA. 



A recent author remarks as to the various species of the Scalidge that for the 

 most part they are " tres difficiles a determiner," I am the more fortunate, 

 therefore, that in studying this group I have been able to avail myself of the special 

 knowledge and experience of such an expert as M. de Boury. [Since this was 

 written I have heard with deep regret that my good friend has passed away.] 



Dr. W. H. Dall proposes to use the generic term Ejntonium (Bolten, 1798), 

 instead of Scala,^ but so far as I know the former has not been adopted by 

 European conchologists. The alteration seems to me undesirable, as Scalii forms 

 the root-word of most of the new sub-generic names of the present group. 



Unfortunately there has been, and still is, considerable difference of opinion 

 as to the use, generic and sub-generic, of some of the names which have been 

 adopted by our best authorities. As the present memoir is intended primarily for 

 the use of geologists, and specially for students of the Crag, to whom as a rule such 

 controversies have but little interest, it seems desirable to retain the old generic 

 name of Scala {8calaria), hy which they have been known for so long, for all the 

 species here dealt with, using the subsidiary names as sub-generic only. 



As urged in my first volume, the introduction of new generic names, now so 

 much in vogue, is bewildering and not helpful to the geological student who has 

 the old text-books to work with and the old lists of fossils to consult. It should 

 be avoided so far as practicable in works like the present, though each case must 

 be decided on its own merits. 



Sith-genus SPINISCALA, de Boury, 1910. 

 Scala (Spiniscala) Trevelyana (Leach). Plate XLVIII, figs, lo, 14. 



1822. Scalaria Trevelyana (Leach) iu Winch, Ami. Pliil., vol. xx, p. 434. 



1846. Scalaria Trevellyana, Loveu, K. Sveusk. Vt't.-Akad. Forh., vol. iii, p. 88, no. 118. 



1853. Scalaria Trevelyana, Forbes and Hanley, Brit. Moll., vol. iii, p. 213, pi. Ixx, figs. 7, 8. 



1859. Scalaria Trevelyana, Or. B. Sowerby, 111. Iiid. Brit. Shells, pi. xv, fig. 19. 



1867—84. Scalaria Trevelyana, Jeffreys, Brit. Conch., vol. iv, p. 93, 1867 ; vol. v, p. 209, pi. Ixxi, 



fig. 4, 1869; in Prestwich, Quart. Journ. Geol. Soc, vol. xxvii, p. 491, 1871; Proc. Zool. Soc, 



p. 137, 1884. 

 1873 — 6. Scalaria Trevelyana, Seguenza, Boll. R. Com. Geol. Ital., vol. iv, p. 356, no. 324, 1873; 



vol. V, p. 282, no. 117, 1874; vol. vii, p. 98, no. 617, 1876. 

 1890. Scalaria Trevelyana, de Boury, Boll. Soc. Malac. Ital., vol. xlv, p. 291, no. 68. 

 1890. Scalaria Trevelyana, Carus, Prod. Faun. Medit., vol. ii, p. 293. 

 1890 — 1. Fascoscala Turtonis, var. Trevelyana, Sacco, Boll. Soc. Geol. Ital., vol. ix, p. 316, no. 5140, 



1890; Fuscoscala Trevelyana, Moll. Terr. Terz. Piem., pt. ix, p. 19, 1891. 

 1892. Scalaria Trevelyana, Locard, Coq. mar. Cotes de France, p. 127. 



1901. Scalaria Trevelyana, Br^gger, Norges geol. Uuders^gelse, no. 31, p. 661, pi. xvi, fig. 18. 

 1903. Scalaria (Linctoscala) irevelyana, Kobelt, Icon, schalentrag. europ. Meerosconch., vol. iii, p 20, 



pi. Ixi, figs. 11—13. 

 1912. Scala (Sjmiiscala) Trevelyana, Cossmann, Ess. Pak'oconch. conipar., vol. ix, p. 32. 



1 Proc. U.S. Nat. Mus., vol. liii, no. 2217, p. 471, 1917. 



