518 PLIOCENE MOLLUSCA. 



of them agreeing more or less nearly with those of Wood. The tliird, however, is 

 different. As figured by Sowerby, it is a distinct form easily separated from other 

 varieties of this species by its prominent and rather distant ribs. As Sowerby' s 

 Memoir is considerably the older, his shell must be accepted as the true var. rugosa, 

 Wood's name being withdrawn in its favour as well as one of those described by 

 me (in error) as var. costata in PI. Ill, fig. 15, of Vol. I. For Wood's shell I 

 propose the varietal name Woodii, see below, while my fig. 15 becomes var. rugosa. 

 Among a large number of specimens of this variable species it is not easy 

 to refer all of them to those that may be fairly regarded as varietal types, as some 

 are of an intermediate character. It may be desirable, hoAvever, to figure examples 

 of those that may be regarded as specifically distinct, of which I have about ten kinds 

 in my collection. 



Var. Woodii, nov. Plate XLVI, fig. 6. 



1848. Nassa reticosa, var. riujosa, S. V. Wood, Moii. Crag Moll., pt. i, p. 33, pi. iii, fig. 10 I. 



RemarJcs. — For reasons just given Wood's varietal name of rugosa must be 

 discontinued in favour of Sowerby's costated variety. I substitute for it that 

 given above in remembrance of my old friend. The specimen now given is from 

 the Crowfoot Collection and was found at Butle}^ ; its whorls are wide and buccini- 

 form as in that figured by Wood. 



Var. elongata (J. Sowerby). Plate XLVI, fig. 4. 



1818. Buccinum elongatnm, J. Sowerby, Min. Conch., vol. ii, p. 15, pi. ex, fig. 1. 



1842—48. Nassa elomjata, S. V. Wood, Ann. Mag. Nat. Hist. [1], vol. ix, p. 539, 1842 ; N. reticosa, 

 var. eloiKjafa, Mon. Crag Moll., pt. i, p. 33, i>\. iii, fig. 10 c. 



Benin rlcs. — Wood's figure of this variety corresponds very closely with what is 

 one of the most distinct and abundant forms of N. reticosa in the Eno-lish Craof. 

 It is elongate in form, generally rather thin and fragile, the longitudinal costre being 

 fine, inconspicuous and numerous — confined, as a rule, to the upper whorls. Nyst's 

 figures of this species are also elongate, but the sculpture is coarser and the ribs 

 stronger and less numerous. It may be interesting to notice that a closely allied, if 

 if not identical shell, Nassa auhigiensls (fig. 8), occurs in the Lower Pliocene of Bosq 

 d'Aubigny in the south-west of France, a specimen of which I have received from 

 my friend M. Dautzenberg and is here given for comparison. This is interesting, 

 suggesting a southern origin for this remarkable group of molluscs. Appearing first 

 in the Coralline Crag of Sutton, in which they are very rare, they become abundant 

 in that of Boy ton, where Mr. Bell informs me they were formerly obtained in great 

 numbers. From the Waltonian Crag he and I have obtained about 500 specimens, 

 including rarities. In the later beds of the Red Crag, on the contrary, they became 

 less common and finally disappeared, killed off possibly by the increasing cold. I 



