DRILLIA ICENORUM. 221 



suture distinct ; mouth oval, angulate above ; canal very short, twisted, wide and 

 open ; inner lip forming a glaze on the pillar, with a small umbilicus to the left of 

 it ; pillar flexuous. 



Dimensions. — L. 16 — 18 mm. B. G — 7 mm. 



Distribution. — Not known living. 



Fossil : Coralline Crag : Sutton, Gedgrave, Boyton. Waltonian : 

 Walton-on-Naze, Little Oakley. Newbournian : Waldringfield. Scaldisien : 

 Antwerp. 



Bemarhs. — In Wood's Monograph of 1848 {op. cit.) two very distinct shells 

 were referred to P. semicolon, Sowerby, an Eocene species from Bracklesham. 

 Recognising subsequently the difference between them, as well as from the latter, 

 he proposed that the one should be known as P. icenoraiii, the other as P. hipnnc- 

 tula, both of which specific names I adopt. 



The former, that now in question, resembles P. denticnla in sculpture, but is 

 easily distinguished from it, being a true Drlllia. It is not a very abundant Crag 

 shell, but may be found in most collections, generally from the earlier horizons. 

 It has been reported from several localities in the Coralline Crag. Prof. 

 Kendall obtained it at Walton, I have several imperfect specimens from Oakley, 

 and there is one from Waldringfield in the Ipswich Museum. I have another, 

 moreover, in my collection from the Scaldisien of Antwerp. The generally 

 unworn condition of these fossils lends but little support to the view that they are 

 derivative. 



The typical D. icenormn is only known from the Pliocene beds of the Anglo- 

 Belgian basin. Prof, von Koenen identifies it doubtfully with Pleurotoma 

 Hosiusi} but from a specimen of the latter which he has kindly sent me for com- 

 parison I believe they are quite different. 



Var. elongata, nov. Plate XXVII, fig. 18. 



1872. Pleurotoma coronata, S. V. Wood, Mon. Crag Moll., 1st Siippl., pt. i, p. 32, ].l. vi, fig. 4. 



Dimensions. — L. 20 mm. B. 6 mm. 



Distribution. — Not knowm livinsf. 



Fossil: Coralline Crag: G-edgrave, Boyton. Newbournian: Wald- 

 ringfield. 



Remarks. — This form, the type specimen of which is in the Ipswich Museum, 

 seems to be merely an elongated and slender variety of D. icenormn. There are 

 two others from the Coralline Crag of a somewhat intermediate character at York. 



The Miocene species to which the present form was referred by Wood is a true 



1 Mioc. Nord-Deiitsch. Moll. Faun., vol. i, p. 105, pi. ii, fig. 12, 1872. 



