556 PLIOCENE MOLLUSCA. 



number of ribs, from 14 to 21 . The S. minuta of Sign. Cerulli-Irelli is considered 

 by M, de Boury to be a different species, for which he proposes the specific name 

 tuhnlata. I am informed that the Belo^ian shells are the same as those from the 

 English Crag. 



o 



Scala (Hyaloscala) clathratula (G. Adams). Plate XLVIII, figs. 28—30. 



1798. Turbo dathrafuhis, G. Adams, Ess. Micros., ed. 2, p. 637, pi. xiv, fig. 19. 



1803—8. Turbo dathratulus, Montagu, Test. Brit., vol. ii, p. 297, 1803 ; Suppl., p. 124, 1808. 



1819. Turbo dathratulus, Turton, Conch. Diet., p. 208. 



1853. Scalaria dathratula, Forbes and Hanley, Brit. Moll., vol. iii, p. 209, pi. Ixx, figs. 3, 4. 



1859. Scalaria dathratula, G. B. Sowerbj, 111. Ind. Brit. Shells, pi. xv, fig. 20. 



1867—69. Scalaria dathratula, .Jeffreys, Brit. Conch., vol. iv, p. 96, 1867; vol. v, p. 210, pi. Ixxi, 



fig. 5, 1869. 

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

 1890. Hyaloscala clathratula, de Boury, Boll. Soc. Malac. Ital., vol. xiv, p. 247. 

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

 1912. Scalaria (Hyaloscala) clathratula, Cossmann, Ess. Palcoconcli. corapar., vol. ix, p. 39. 



Bemarks. — It may be interesting to illustrate the difference between the Crag 

 8. minuta and the recent *S^. dathratula by comparing some verified specimens of 

 the latter with those of the former already figured. 



Fig. 30 in my plate represents a recent and minute 8. clathratula from the 

 Gironde, which I received from M. Dautzenberg ; fig. 28 is a much larger and also 

 recent variety of that species from the Holmes Collection at the Norwich Museum ; 

 fig. 29 is taken from one preserved at the York Museum, which was dredged from 

 the Dogger-bank. It is of the minute type. 



Both species vary considerably in size ; otherwise they are considered to 

 maintain the same general character. 



8. clathratula has been recorded from the Miocene of Messina by Seguenza and 

 from the Pliocene of Biot by Alfred Bell, but the specimens cannot now be traced. 



8uh-cjenus ACRILLA, H. Adams, 1860. 

 Scala (Acrilla) exsemicostata (Sacco). Plate XLVIII, fig. 7. 



1874. Scalaria semicostata, S. V. Wood, Mon. Crag Moll., 1st Suppl., pt. ii, p. 183, add. pi., fig. 1. 

 1891. Scalaria {Acrilla) exsemicostata, Sacco, Moll. Terr. Terz. Piem., pt. ix, pp. 60, &*? . 

 1918. Scala (Acrilla) exsemicostata, de Boury, MS. 



8'pecific Characters. — Shell slender, subulate ; whorls about 12, convex ; orna- 

 mented by numerous thin and delicate costa3 with sharp edges smaller than the 

 intervening spaces, and by exceedingly fine and inconspicuous spiral lines, the last 



