326 PLIOCENE MOLLUSC A 



While a part of the Manx- Wexford mollusca have a distinctly Pliocene facies, 

 the Nassas do not indicate any close connection between the eastern and the 

 western Pliocene fauna. One misses in the deposits of the latter region the species 

 of Nassa so constantly and so abundantly present in the Red Crag, especially in 

 the earlier part of it, such as the many different varieties of N. reticosa, 

 N. granulata, X. propinqua, and N. elegans, which are either unrecorded or but 

 very rarely met with in the western area; the two most abundant species of the 

 latter being N. incrassata and N. reticulata, both of them common as recent on 

 the British coasts, but as fossil, representative in the east of England of the 

 Pleistocene rather than of the Pliocene deposits, although dating back in other 

 areas to Miocene times. 



The Himse are small shells with a short canal, a thickened and varicose lip 

 denticulated within, and a reticulated sculpture, JV. incrassata being taken as the 

 type. Some other of the smaller species described in my first part, such as 

 N. elegans, N. consociata, N. granulata, and N~. tnronica are included in this group. 



Var. j3. Plate V, figs. 25, 26. 



1848 

 1868 

 1901 

 1910 

 1915 



Nassa incrassata, S. V. Wood, Mon. Crag Moll., pt. i, p. 29, pi. iii, fig. 4. 



Nassa incrassata, G. O. Sars, Moll. Reg. Arct. Norv., pp. 253, 362, pi. xxiv, fig. 1. 



Nassa incrassata, Br^gger, Norges geol. Uiiders^gelse, no. 31, p. 658, pi. xviii, fig. 24. 



Nassa. incrassata, 0yen, Kongl. Norske Vid.-Selsk. Skrift,, no. ix, pp. 27 et seq. 



Nassa incrassata, var. /3, F. W. Harmer, Plioc. Moll. Gt. Brit,, pt. i, p. 88, pi. v, figs. 25, 26. 



Varietal Characters. — Smaller, thinner, and more delicate than the type, with 

 finer sculpture. 



Remarks. — The Butley specimen shown on PI. V, fig. 25, represents, as far as 

 my experience goes, the variety most commonly found in the later zones of the 

 Crag ; those from Wexford are all of the strong and British type. The two figures 

 should be compared. 



Nassa (Hima) pygmaea (Lamarck). Plate XXXIV, figs. 6, 7. 



1822-43. Banella pygmsea, Lamarck, Hist. nat. Auiin. sans Vert., vol. vii, p. 154, no. 14, 1822 ; 



ed. 2 (Deshayes), vol. ix, p. 550, no. 14, 1843. 

 1826. Tritonia varicosa, Turton, Zool. Journ., vol. ii, p. 365, pi. xiii, fig. 7. 

 1853. Nassa pygmsea, Forbes and Hanley, Brit, Moll., vol. iii, p. 394, pi. cviii, figs. 5, 6. 

 1867-71. Nassa pygmsea, Jeffreys, Brit, Conch., vol. iv, p. 354, 1867 ; vol. v, p. 219, pi. lxxxviii, fig. 2, 



1869; in Prestwich, Quart. Journ. Geol. Soc, vol. xxvii, p. 489, 1871. 

 1850-72. Nassa pygmsea, S. V. Wood, Mon. Crag Moll., pt, ii, p. 315, pi. xxxi, fig. 5, 1850 ; 1st Suppl., 



pt. i, p. 12, pi. vi, fig. 6, 1872. 



1872. Nassa pygmsea, A. and E. Bell, Proc. Geol. Assoc, vol. ii, p. 213. 



1873. Nassa pygmsea, Seguenza, Boll. R. Com. Geol. Peal., vol. iv, p. 300, no. 151. 



