GASTEROPODA. 7 
This was found by Mr. Bell, to whom I am indebted for the use of the specimen for 
the above figure ; it is the only one I have seen from the Crag. 
Lirrorina rupis, Maton. Supplement, Tab. V, figs. 9 and 10 a, 6. 
In my Monograph, vol. i, p. 118, Tab. X, fig. 14, a—4, I have given figures and 
descriptions of a variety of forms of shells belonging to the genus Li/torina, from the 
Fluvio-marine Crag of Norfolk and Suffolk, which I had considered as all belonging to 
one species, /ifforea, and I have here had figured two or three more to show the 
extraordinary range in variation to which they had been subject. The British Con- 
chologists, although they have kept separate several forms of this genus, have no 
accordance respecting specific division. 
I have obtained a very large number of specimens of Zet/orire from the Fluvio- 
marine Chillesford bed, at Horstead and Coltishall, and from the Lower Glacial sand at 
Belaugh, and these correspond principally with the form usually seen in our markets. 
With these, as might be supposed, are small or young specimens strongly marked with 
spiral striae and with a well-defined suture, while the large or full-grown specimens are 
nearly smooth. ‘Two or three of the distorted figures of Lztforina, ‘Crag Mol.,’ vol. 1, 
Tab. X, fig. 14, may probably be referred to what is called rads. Mr. Jeffreys says 
(vol. ili, p. 367) that rudis is viviparous, and /i/torea oviparous. If this be so, that 
distinction might entitle them to be considered as more than specifically distinct; but 
as far as their testaceous covering goes there seems so much intermingling of character 
between rudis and Jittorea, not to speak of the numerous other forms treated as species 
or varieties, that I confess to the greatest uncertainty in assigning shells to these 
respective species separately ; what seems tobe Z. rudis from Bramerton is shown in 
‘ab. V, fig. 9; anda distortion of the same species from the same place, put into my hands 
by Mr. Horace Woodward, is shown in fig. 10. Z. dittorea occurs also in the Middle 
Glacial at Hopton and Billockby, in the Upper Glacial at Bridlington, and in the Post- 
Glacial Gravels of March, Hunstanton, and Kelsea Hill, and in the Nar Brickearth. 
Lacuna reticutata, 8. Wood. Crag Moll., vol. i, p. 122, Tab. XII, fig. 10. 
MacrompHaLus RETIcULATUS, S. Wood. (Catalogue of shells from the Crag.) Ann. 
Nat. Hist., 1842, p. 537. 
This shell is excessively rare to my researches, and I am unable to give to it any 
additional particulars; it does not strictly conform to the characters of the genus as 
generally described, but it has a broad and flattened pillar lip or elongated umbilicus ; 
it nearly resembles Lacuna elegans, Deshayes, ‘ An. sans Vert. du Bas. de Par.,’ vol. ui, 
p. 371, Pl. XVII, figs. 4—6, but it is probably distinct. Another species, somewhat re- 
sembling it,is placed in the same genus by Dr. von Koenen, ‘Mittel Olig. Norddeutschlands,’ 
