372 PLIOCENE MOLLUSCA. 



species in question is said by M. Locard to be a variable one ; although in some 

 respects noi unlike 8. tortuosus and S. gracilis, it is considered by himself and by 

 the other authorities quoted above to be specifically distinct. I know of nothing 

 else in the Crag to which our shell can be satisfactorily referred. Like the 8. 

 menapix of A. Bell, figured above (p. 186, PI. XXIII, figs. 17 — V.)), it is unknown 

 from the eastern basin of the British Pliocene. 



Sipho gracilis (Da Costa). Plate XX, figs. 3, 4; Plate XXXVIII, figs. 1, 2. 



1887. Neptunea gracilis, Kobelt, Icon, schaleutrag. europ. Meeresconch., vol. i, p. 72, pi. iii, fig. 4. 



1890. Fusus gracilis, A. Bell, Rep. Brit. Assoc. (Leeds), pp. 410, 414, 417. 



1892. Neptunea gracilis, Locard, Coq. mar. Cotes de France, p. 111. 



1894. Fusus gracilis, Kendall, Journ. Isle of Man Nat. Hist. Soc, vol. xii, p. 419. 



1901. Sipho gracilis, Cossmann, Ess. Paleoconch. compar., vol. iv, p. 100, pi. iv, fig. 12. 



1914. Sipho gracilis, F. W. Harmer, Plioc. Moll. Gt. Brit,, pt. i, p. 175, pi. xx, figs. 3, 4. 



Remarks. — As stated on p. 176 of the present work, the Belgian fossil described 

 by Nyst as Fusus gracilis approaches more nearly the one I have taken as the type 

 of the Crag S. curtus, Jeffreys, and is probably the same. 1 The two forms are 

 closely allied, though my continental friends follow Jeffreys and Wood in considering 

 them specifically distinct. From a geological point of view the matter does not 

 seem to me of great importance, so long as their stratigraphical position can be 

 clearly defined. I have found both at Oakley, but S. curtus with its many varieties 

 is the more abundant at that place. On the contrary, among the Siphos lately 

 received from Wexford the specimens belonging to this group are generally of the 

 recent gracilis type, one or two approaching the slender variety Coidsoni, of which 

 an example was shown on my PI. XX, fig. 6. Two of the Wexford forms of 

 8. gracilis are represented by figs. 1 and 2 of PI. XXXVIII. 



Var. convoluta (Jeffreys). Plate XXV, figs. 6, 7; Plate XXXVIII, figs. 3, 4. 



1914-5. Sipho gracilis, var. convoluta, F. W. Harmer, Plioc. Moll. Gt. Brit,, pt, i, p. 178, 1914; pt. ii, 

 pi. xxv, figs. 6, 7, 1915. 



Distribution. — (Additional) Waltonian Crag : Little Oakley. Wexford gravels. 



Remarks. — The Wexford fossil figured under the present name seems to 

 correspond with this variety of S. gracilis, which may be distinguished from the 

 type by its elongated spire, its more convex whorls, and its comparatively slender 

 form. With the other Siphos from the same locality, it is thicker and stronger 

 than those found in British seas at the present day. 



1 This name has always seemed to me exceedingly inappropriate. 



