MONOGRAPH OF BRITISH LAND AND FRESHWATER MOLLUSCA. 195 
Susp-GENus Janulus Lowe. 
Pyramidula suttonensis (S. V. Wood). 
Helix suttonensis 8S. V. Wood, Monog. Crag. Moll., 1872, p. 2, pl. 1, ff. 2 a-e. 
SHELL depressly orbicular, composed of about seven slowly increasing and 
almost subangulate WHORLS, and a moderately exserted SPIRE; the apical whorl 
is smooth, but the upper surface of the rest of the shell is beautifully costulate 
by thick, round, and transverse ridges at regular intervals, of which there are 
about eighty on the outer volution ; SUTURE very deep and distinct, the edges of 
the whorls being slightly elevated at their junction with the preceding volution. 
The under surface is very convex and quite smooth, and the UMBILICUS small but 
funnel-shaped and deep. APERTURE narrowly lunate and slightly reflected. 
Diam. about 6 mill. ; alt. 34 mill. 
Fic. 218.—//edix suttonensis (S. V. Wood) enlarged (after Wood). 
P. suttonensis is apparently most nearly related to P. bifrons, to which 
it bears a close resemblance, differing, however, in its more risen spire, 
more numerous whorls, and in the number and size of the costulate ridges. 
The affinities of the present and the succeeding species are with the 
primitive molluscan fauna now inhabiting the Island of Madeira. 
BRITISH ISLES. 
Pliocene— Mr. Wood discovered this unique specimen (now in the British 
Museum) in 1867 in the truly marine formation, the coralline crag at Sutton, East 
Suffolk. 
Pyramidula rysa (S. V. Wood). 
Helix rysa S. V. Wood, Mon. Crag Moll., 1848, p. 4, pl. f. 1. 
Helix rufescens var. 7 J. G. Jeffreys, Quart. Journ. Geol. Soc., 1871, p. 493. 
SHELL depressly orbicular, about equally convex above and below, the upper 
surface rugosely striated or rather corrugated and faintly striate below ; WHORLS 
seven, obtusely but distinctly keeled at the periphery, the keel being visible at the 
SUTURE on the upper whorls ; APERTURE broadly lunate, with a sharp and reflected 
peristome ; UMBILICUS distinctly, but not widely open. 
Diam. 16 mill. ; alt. 6 mill. 
Fic. 249.—Helix rysa (S. V. Wood) enlarged (after Wood). 
P. rysa also has its affinities and relationship with the peculiar species 
now restricted to the Atlantic Isles, although Dr. Jeffreys was inclined at 
one time to regard this species as a variety of //. rufescens; but the 
present shell is larger, has seven volutions, is more distinctly corrugated 
above, and the keel is visible to the apex. 
BRITISH ISLES. 
Mid-Pliocene—The type specimen of this species was, according to Mr. Wocd, 
found by Mr. G. 8. Gibson, of Saffron Walden, within the aperture of a Buccinum 
undatum, in the Red Crag of Walton-on-the-Naze, North Essex, and is now 
deposited in the Saffron Walden Museum. <A second specimen has since been 
obtained by Mr. Canham from the Coprolite diggers at Waldringfield, East Suffolk. 
