30 SUPPLEMENT TO THE CRAG MOLLUSCA. 



Pleurotoma bipunctula, S. Wood. Crag Moll., vol. i, p. 54, Tab. VI, fig. 3 b (as P. 



semicolon). 



This shell, which I also doubtfully referred as var. b of PI. semicolon, J. Sow, is, I am 

 now satisfied, distinct from that species. It differs from the preceding PI. Icenorum in 

 several points, viz. in its ornament, in its more fusiform shape, and in the position of the 

 sinus of the outer lip, which in this is more central, as indicated by the knobs left on the 

 volution. It somewhat resembles PL bicatena, Grat., but I believe it is different, and it 

 differs from the Eocene PI. denticula. 



Mr. Bell, in the ' Ann. and Mag. Nat. Hist./ 1871, gives the name of Pleur. pannum to 

 my shell. It possibly may be so, but I have not been able to see a specimen of that 

 Bordeaux species. The description given by Basterot is insufficient, so that I could not 

 venture to refer my shell in reliance on that, and the figure of this species by 

 Bellardi, ' Piedm. Foss.,' Tab. II, fig. 2, is so inadequate, that it does not represent the 

 position of the sinus, neither does his description (p. 27) supply the deficiency. I have 

 therefore given to it a new name. 



Pleurotoma linearis. Crag Moll., vol. i, p. 56, Tab. VII, fig. 2. 



Localities. Cor. Crag, Sutton. Red Crag, Sutton and Butley. Chillesford Bed, 

 Aldeby {Croiofoot and Dowson). Middle Glacial, Billockby. 



The red crag form of this shell figured in the 'Crag Mollusca' as the recent linearis, 

 possesses the same number of ribs and the same sculpture as on the recent shell, but a speci- 

 men from the Middle Glacial sand of Billockby, in a state of preservation unusually perfect for 

 that formation, departs from the recent form in respect that it possesses fourteen ribs on the 

 body whorl and twelve on the next, or two beyond the respective numbers on these 

 whorls possessed by recent shells. I have not, however, thought it necessary to figure 

 the Middle Glacial shell, or to assign it as a new species, which, however, it may 

 possibly be, as it approaches perpulc/ira in the character of its ribs and of its 

 striation, though not identical with that species. 



Pleurotoma elegantula, A. Bell. Supplement, Tab. Ill, fig. 8. 



Pleurotoma elegantula, A. Bell. Add. aod Mag. Nat. Hist., p. 8, May, 18/1. 



Spec. Char. PI. " Shell stoutly fusiform ; whorls 7 — 9 convex, ornamented with close- 

 set ribs 10 — 12 on the second whorl {penultimate ?) ; suture deep ; mouth and canal open ; 

 pillar lip reflected ; notch sinuated rather deeply." — A. Bell. 



