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404 HELICIGONA LAPICIDA. 
Protective Resemblance. — The similarity of this snail to other 
objects has been noted by several observers; Mr. Cobbold exhibited at the 
meeting of the Essex Field Club a species of Medicago, the fruit of which 
so closely resembled a snail as to give it the name of the “Snail Plant,” 
and which simulates the shell of 77. dapicida so closely that the shell could 
scarcely be distinguished from the fruit. 
Mr. J. F. Whiteaves has also remarked that he has found this species on 
bramble in Oxfordshire, and that it is difficult to detect in such situations, 
as the shell resembles in colour the dark purple hue of the plant ; while 
Mr. Step has found that when at rest on beech trunks it is an exact 
counterpart of the low-knobbed excrescences on the smooth grey bark, and 
when afhixed to the bottom framing of park palings it as closely resembles 
the heads of the iron bolts with which the framing is put together. 
Geological Distribution.—Not as yet reliably found below the Plio- 
cene strata, from whence it is reported by M. Locard; it. is, however, 
present in many beds of later age over a considerable region. 
‘he specimens from the Oligocene limestone beds at Sconce and else- 
where in the Isle of Wight, doubtfully referred to this species by Mr. F. E. 
Edwards, have here been regarded as another species, Plectotropis tropiferc, 
which belongs to a group of mollusks formerly inhabiting the European 
region, but long ago expelled therefrom, and now finding refuge chiefly 
among the Asiatic Islands of the Eastern Pacifie Ocean, which are its 
metropolis at the present day. 
MiocenrE.—One example found by Wollaston at Zimbral d’ Area, Porto 
Santo, Madeira, in the fossiliferous beds ascribed by Dr. Boog Watson to 
the Miocene age, but which M. Locard records as late Pleistocene. 
PLiocENk.—Recorded by M. Locard from the Lower Pliocene beds of 
Hauterive in the department of the Dréme, France. 
Oxiaocenr.—Mr. W. G. Blatch has found specimens in the Barton beds 
in South Hampshire. 
PLEISTOcENE.—In West Kent, it has been discovered in the Ightham 
fissure near Wrotham by Mr. W. J. Lewis Abbott. 
In North Essex, it was recorded by Prof. Morris from the freshwater 
marls of Copford and Clacton. In South Essex, it has been recorded from 
Crayford, but according to Mr. B. B. Woodward probably erroneously. 
In Cambridge, Mrs. McKenny Hughes records it from the gravel beds 
at Barnwell Abbey and at Grantchester. 
In Germany, it is recorded from tufa at Weimar, Burgtonna, and Muhl- 
hausen, Thuringia, by Dr. Sandberger ; from the tufa at Streitberg, Fran- 
conia, by Dr. von Ihering; and the var. grosswlarie from 'huringian 
diluvium by Dr. Richter. 
In France, it is recorded by Dr. Sandberger from the Upper Pleistocene 
at Clichy, Seine-et-Oise ; by M. Locard from the deposits at Paris, the 
Somme Valley, and at Valliéres-les-Grandes, Indre-et-Loire. 
Drs. Grateloup and_Raulin record it under the name of Helix lapicidites 
from the Aquitanian deposits, and as Helix lapicida-minima from those of 
Paris; M. Bouillet as_abundant in the cellular 'l'ravertin, and in the Ara- 
gonite between Coudes and Montpeyroux, Puy-de-Déme, and he also cites 
it from the breccia of Nimes, Gard, on the authority of Brard; and from 
that of Nice, Alpes Maritimes, on the authority of M. de la Groye. 
