GASTEROPODA. 95 



smooth (which, however, may be accidental), and it has a projecting shoulder to the 

 volution ; perhaps it would be more correctly placed either in Tornatina or Actceonina. 



I presume that this is the shell called exilis by Mr. Jeffreys in his list to Mr. 

 Prestwich's Red Crag paper, p. 486. 



Chiton discrepans? Broion. Supplement, Tab. IV, fig. 27. 



Chiton discrepans, Brown. Conch., Grt. Brit., pi. xxxv, fig. 20, 1827. 



— — Forb. and Hani. Brit. Moll., vol. ii, p. 396, pi. 58, fig. 4. 



— crinitus, G. B. Sow. Desc. Cat. Brit. Chitones, p. 2, fig. 88 — 93 ; 



Ency. Method., pi. 163, fig. 11—17. 



Locality. Coralline Crag, Sutton. 



The figure above referred to represents the valve of a Chiton, which I have lately 

 found, and which I have assigned to the above-named British species, though with some 

 slight hesitation ; my specimen appears to be the third or fourth valve with the susten- 

 tacula quite perfect, and these have a peculiar form. The length of the valve is about 

 equal to the breadth of one of its sides, and the ornamentation appears to correspond to 

 that of the shell to which it is here assigned. Unfortunately, in the works upon British 

 Conchology we have neither represented, nor described, the form or magnitude of these 

 processes to the valves, which are, in my opinion, good auxiliary characters. This central 

 valve now figured seems to differ from those of fascicularis in being more rounded at the 

 lateral posterior termination of the valve, and the sustentacula are rather larger. We are 

 not likely for some time to obtain a fossil with all the valves in position, so that we must 

 do the best we can with the materials we possess, and I have given my figure as one step 

 towards a correct determination. 



Chiton Rissoi, Payr. Crag Moll, vol. i, p. 186, Tab. XX, fig. 11. 



My Crag shell, which I referred as above, is regarded as Ch. cinereus, Linn., by Mr. 

 Jeffreys (' Quart. Journ.,' vol. 27, p. 143). My Crag valves form a perfectly semicircular 

 arch, without any angularity or pointed keystone like those of cinereus, and I have 

 therefore retained my original name. 



Chiton strigillatus, S. Wood. Crag Moll., vol. i, p. 186, Tab. XX, fig. 10. 



This may probably be Chiton Hanleyi of the ' British Conchologists.' 

 In the ' Geol. of Norfolk' by S. Woodward, published in 1833, is the name of Chiton 

 octovalvis (p. 44), and this name is repeated by his son Dr. S. P. Woodward, in his list 



