ange, 
Number of pulsations 
t scale, 
a A 
—————— 
Thermal r 
Fahrenhei 
per minute, 
which may possibly account for certain discrepancies now observed. 
HWYALINIA CELLARIA. DO 
Though possessing so frail a shell and so delicate an epiphragin, this 
species can brave with impunity such severe frosts that //e/ia nemoralis 
and #7. hortensis submitted to the same conditions invariably perish. 
The average rate of progression of //. cellaria@ when crawling on a 
smooth surface has been established as nearly two inches per minute or 
at the rate of a mile in rather less than twenty-two days. 
The vertical lines connect the corresponding points of temperature and pulse rate. 
=== =S === a= = = 
Fa = 
=== 
ag 
35° Bay 
30° 30° 
25 25 
20 20 
15 15 
10 10 
5 5 
———— ‘O 
¥ 
v 
‘aqnuru sad 
suonesind jo 1aquinyn 
‘ayeos Waquaiye gy 
Fic. 68.—Diagram of the pulsations of the heart of //yadinta cel/aria, illustrating the correlation of its 
activity with the changes of temperature. 
The susceptibility of the heart’s action to changes of temperature varies 
somewhat in different individuals, but is also influenced by age, health, 
and probably by other causes, whose action is not yet appreciated, and 
The 
illustrative diagram of the correlation of temperature and heart-pulsation 
represents the results of a large number of observations by the late Mr. 
Charles Ashford and myself. 
at Harwich, Clacton, and Copford in North Essex. 
Parasites and Enemies.—//. celluria in spite of its retiring habits, 
is greatly preyed upon by thrushes, blackbirds, and starlings, and the 
shells may be found quite perfect in their crops. 
Internally, they are also liable to be infested with a long and filiform 
parasitic worm, which has not yet been identified. 
Geological History.—Hyulinia cellaria has been reported from many 
deposits of Pleistocene and Holocene age, both in this country and abroad. 
PLEISTOCENE.—It is recorded by Morris from the Upper Pleistocene beds 
In Cambridgeshire, 
Mrs. McKenny Hughes reports it from the gravel pits about Barnwell 
Abbey and Grantchester; while Mr. A. Santer Kennard informs me that 
it is abundant in the Ightham fissure in West Kent, where the specimens 
vary greatly in the height of spire. 
It has also been found at Hoxne in 
East Suffolk; in the Happaway Cavern, Devonshire; at Newquay in 
Cornwall: and in Kesh Cave, co. Sligo, Ireland. 
In Germany, it is recorded from Schwansbeck near Halberstadt in 
Prussian Saxony, and Sandberger records it as found commonly in the 
Upper and Middle Pleistocene tufaceous-deposits at Weimar, Burgtonna, 
‘Q5uUeI [BULIAY T, 
