HELIX PISANA. at 
honoured were based upon structural differences of the animal inhabitant, 
and the bulk not even figured by their authors, though verbosely described, 
but in such general terms that little aid to identification is afforded, and 
judging from an examination of a series of authentic types in the col- 
lection of the Muséum dHistoire Naturelle of Paris, these so-called 
species are allowed so great a range of variation 
and are so hopelessly intermingled that little 
systematic value can be attached to them. 
Dr. Germain describes and figures a specimen 
which may be known as var. brungulata, collected 
by M. de Kerville from the dunes of 'Tabarka, BiG. 422. — Helix pisana 
Tunis, which shows a basal angulation in addition‘), (agwlata. 
to the more usual supra-peripheral one. hee DR Canes 
(after Dr. Germain). 
As in other fasciate species, the pigment secreting cells may occasion- 
ally atrophy at the termination of a growth . 
period, before the maturity of the shell takes 
place, the growth afterwards made being wholly 
or partially deficient of the banding present on 
the earlier whorls, or on the contrary, the secret- 
ory power may be latent or undeveloped in the 
young shell, and gradually or more rarely sud- eee eRe pisana 
» Muller, X s 
denly develop at the commencement of a growth Tenby, Mr. J.R.B.Masefield. 
period and continue in full vigour until maturity Showing abrupt commence- 
has been attained ment of distinct banding. 
Achy } . 
The delicacy of the lear banding is also an indication that owing to its 
exposed habits of life the banding is breaking-up and disappearing, for in less 
open and more shaded localities as in gardens and cultivated grounds the 
bands tend to be retained and become more accentuated, and it 1s also in 
those places that the largest shells are found. 
It is a species which accurately reflects the features of its environment, 
and is especially organized to resist great heat and prolonged drought, the 
shell, especially abroad, being most frequently of a dull uniform creamy 
colour, adapted to resist the absorption of the heat to which it may be 
subjected. 
On the Atlantic slope of Morocco the shells become more globose and 
solid with thicker lips, the markings are more brightly coloured, and display 
new arrangements testifying to the unusual features of their environment, 
and it is interesting to observe that M. Pallary ascribes the albinism of this 
species in Morocco to excess of humidity. 
VARIATIONS OF FORM. 
Var. globosior Shuttleworth. 
Helix pisana var. globosior Shuttleworth, Moll. Corse, 1843, p. 10. 
Helix pisana var. globosa Requien, Catal. 1848, p. 44. 
Helix carpiensis and hamadanica Let. et Bourg., Prodr. Mal. Tunis., 1887, p. 86. 
Helix donatii Berthier, Prodr. Mal. Tunis., 1887, p. 82. 
Helix dermot Servain, Prodr. Mal. Tunis., 1887, p. 89. 
Helix radesiana Marés, Prodr. Mal. Vunis., 1887, p. 80. 
Helix lenoleuca Bourguignat, Prodr. Mal. Tunis., 1887, p. 80. 
Helix (Euparypha) pisana vay. egusina Mont., Moll. isole adj. Sicilia, 1892, p. Lo. 
Helix pisana var. globulosa Locard, Conch. Portug., 1899, p. 50. 
Helix pisana var. donnelli Pallary, Journ. de Conch., 1904, p. 52, p. 11, pl. 2, f. 12. 
Helix pisana var. gratiosa Monterosato, MS. 
SHELL more elobular. 
The sub-var. segusina is described as globose, but is also often found in a small 
form, described by M. di Monterosato as minima globosa, which is only 14 mill. in 
diameter and 11 mill. in altitude. 
