176 JOURNAL OF CONCHOLOGY. 
On the Variation of Stilifer Turtoni Brod.—Through the kind- 
ness of three correspondents in Scotland, I have had an opportunity of 
examining a large series, numbering about two hundred specimens, of this 
species obtained off the counties of Forfar, Kincardine, and Aberdeen. The 
range of variation exhibited is surprising. The following forms may be 
worthy of special mention :—-VAR. EX FORMA. SS. Zurtoni Brod. var. 
oblonga nov. (fig. 1). Shell much elongated ; the ultimate and penultimate 
whorls nearly equal in breadth; the suture nearly straight between the 
earlier turns, becoming more and more oblique below. H.3°6 mm.; b. 
2 mm. Three specimens. VAR. EX. COLORE. S. Zzrtonz Brod. var. 
Jactea nov. Shell entirely opaline milk-white, except the apex which retains 
its usual brown tint. This variety is connected with the type by all inter- 
mediate gradations of hue and transparency, but characteristic specimens are 
rare. In addition to the above, a single specimen of an individual abnor- 
Big: Fig. 2. Fig. 26. 
mality occurred, so remarkable as to merit description (figs. 2a, 26). The 
apex, instead of being erect and prominent, is altogether invisible in side view. 
When, however, the shell is looked at from above, it is seen to be lying flat 
and to be surrounded by the next whorl.. The arrangement indeed corresponds 
to that occurring normally in /axthina. This group of departures from the 
typical form of a species is perhaps best designated as I have done, “ indi- 
vidual abnormality,” in contradistinction to ‘‘monstrosity,” a term very 
loosely applied by conchologists to such forms as that described, to the 
effects of external agencies (decollation, erosion, etc.), as well as to mon- 
strosities proper, in which the peculiar characters commence im embryonic 
life (sinistrorsion and true albinism, z.e., of the animal as well as of the 
shell) —GEORGE W. CHASTER. (Read before the Conchologecal Society, 
August 7th, 1895). 
pie nee ae ee 
Physa acuta at Ostend.—Last August, I came across a pond 
full of this species close to Ostend. The shells were, I think, rather thicker 
than those bred in England, as I scraped the encrusting matter off with the 
large blade of my knife without causing any injury. I could find nothing 
else in the pond but a solitary Lzmnea peregra.—LIONEL E. ADAMS, 
Northampton. (Read before the Conchological Society, Oct. 2nd, 1895). 
J.C., viil., Jan. 1896. 
