Ilf) 
MONSTROSITIES — SCALARIFORMITY. 
wliich, according to M. Bonrgnignat, is in its early stages 
sinistrally coiled, and only later tends to become a dextral shell, being 
apparently somewhat analogons in this respect with Anastoma, 
thongh coiled in the opi)osite direction. 
A sinistral shell can he readily recognized by holding the shell with 
the aperture towards the observer and its apex iiointed upwards, when, 
it dextral, the ai)ertnre will he on the observer’s right, and, if sinistral, 
on his left: hnt this simple and easy test does not enable ns to 
detect or recognize those shells which have been subjected to hyper- 
stro])hic develojnnent. 
ScAE.AUiFORMiTY (.sYY^ a tlight of stah's ; and/w;;?^^, form) of the 
shell is the separation or dislocation of the whorls and is a phenomenon 
to which all s])irally coiled shells are liable, possibly owing to some 
internal pecnliarity of, or injury to, the organization of the animal, or, 
at least in some cases, to the adherence 
of extraneous matter to the immature 
shell or other cause interfering with 
the close apposition of one whorl with 
another, and in correlation with the 
amonnt of ohstrnction the obstacle 
offers to the normal growth, the degree 
of scalarity in the shell is dependent, 
as it nsnally follows for the rest of its 
growth the direction tlins accidentally 
given to it. If the interference he 
comparatively slight and near the 
sntnre, a canalicnlate sntnre may he formed, which may continne 
([iiite to the aperture, or may only exist for a limited distance, the 
growth becoming normal after passing beyond the ohstrnction. 
Ilemarkahle examples of extreme scalarity are furnished by the 
ceratoid specimens of //c//,r and 
other species. 
The flatly-coiled or discoid shells of 
P/(niorl>lft are e([nally or even more liable 
to become spirally elevated with more or 
less regnlarity, as in Phtnorbls mdrffiuatm 
monst. cochlea, which may in that state he 
easily mistaken, at a casual glance, for 
Valcaia 'phcinaUs, to wOiich species it hears a great resemblance. 
Fig. 2()2. — Plnnorhis viar- 
ginatus in. cochlea I’rown X 3, 
Fisegale ICau, fiosiierlon, 
Cijllecled I)y Mr. H. Wallis 
Kew, F.Z.S., 
Showing a scalariform shell. 
Fig. 2lil. — Heli.v asf>ei-sa monsl. cornu- 
co/>ia (intclin, 
iMnwnan Sanctuary, near Falmouth, 
Collected by the late Rev. W. Rogers, 
An c.vample of e.vtreme scalarity. 
