GASTEROPODA. 97 
to be one of R. ventricosa, so that duccinea is not known from any newer deposit than 
the Red Crag, in which, moreover, it is extremely rare, and may, even in that Crag, be 
only derivative from the Coraline. 
Rineicuna ventricosa, J. Sow. Crag Moll., vol. i, p. 22, Tab. IV, fig. 1. 
Localities. Coralline Crag, Sutton. Red Crag, Sutton and Butley. Fluvio-marine 
Crag, Bramerton (Woodward), Yarn Hill (Fisher). Chillesford bed, Aldeby (Crowfoot 
and Dowson). 
In the ‘Crag Mollusca’ Ringicula was placed in the section Solenostomata of Pleming 
(Canalifera, Lam.), depending upon the peculiar construction of the shell. Recent 
observations have removed it near to 4cteon, in which position I have here placed it in 
deference to the Malacologists. It is, however, of a very aberrant character, possessing 
as it does a deep siphonal canal, very unlike its present associates. &. ventricosa still 
remains very rare in the Coralline Crag. 
Since my communication in 1870 to the ‘ Ann. and Mag. of Nat. Hist.,’ respecting the 
peculiarity of the Crag shells of this genus, I have found more than a hundred other 
specimens of 2. Juccinea, all in the presumed full-grown condition, that is, with a thickened 
outer lip. Of course this outer lip, while the animal is growing, must necessarily have a 
plain or simple margin, but the peculiarity is that it has so rarely’ died in that condition 
I had imagined, and de so still, that these animals, as also those of Zrivia, completed their 
shell in anticipation of their decease, and that many of the small specimens we find 
are young individuals that have thus assumed the adult form. 
Rissoa aByssicoia? Forbes. Supplement, Tab. VII, fig. 2. 
Rissoa apyssicota, Forbes. Brit. Moll., vol. iii, p. 86, pl. Ixxvii, figs. 1, 2. 
Locality. Cor. Crag, Sutton. Living Britain, Scandinavia, and Mediterranean. 
A single specimen which I have quite recently found in the Cor. Crag of Sutton is 
shown in the above figure. It may, I think, be referred to abyssicola of Forbes. 
CANCELLARIA wirIDULA, Fué. Crag Moll. vol. i, p. 66, Tab. VII, fig. 21, as 
C. castellifer. 
CANCELLARIA VIRIDULA, var. CourHouyr. Supplement, Tab. VI, fig. 12. 
This species is now considered to be the Zritoniwm viridulum of Fabricius’ Fauna 
1 T, indeed, doubt whether a perfect specimen without the thickened lip has occurred in the Crag; the 
few such that I possess appear all of them to have had the thickened lip broken off. 
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