“— 
282 HELIX NEMORALIS. 
At Charlestown, South Carolina, U.S.A., the formerly flourishing colony 
of this species has been practically exterminated and devoured _ by the 
predatory Rumina decollata, which is also an European introduction to 
North America. 
Drilus, a coleopteron, allied to the glow-worm, and also its larva, attack 
and devour H. nemoralis, the larva taking up its abode in the shell of the 
victim, enclosing itself by a fibrous web before undergoing its metamor- 
phoses. The beetle emerges in October. 
The larvee of Lampyris noctiluca, the glow-worm, also feed on the living 
snail, and are believed by Fowler to derive their phosphorescent powers 
from this source. 
The eggs even are not immune from attack, as ants, centipedes, etc., 
devour them whenever found, and mollusks of the same or other species 
will feed upon them, although their greatest enemies would appear to be 
dipterous larvee, which frequently destroy whole broods. 
Distomum leptostomum Olsson in its sexual mature state inhabits the 
intestinal canal of the hedgehog, but its miracidian, sporocyst, and cer- 
carian (Cercaria helicis) stages are passed within the tissues, alimentary 
canal, and liver of Helix nemoralis and other common gastropods, the 
parasite gaining access to its later host, the hedgehog, when the snail is 
devoured. ‘I'he caudal appendage of the young cercarium is occasionally 
retained to a later period, and then probably constitutes the Distomum 
caudatum of Loos. ‘l'his species differs only in its smooth body surface 
and some slight internal modifications from Distomum spinulosum, known 
in its cercarian stage as Cercaria spinulosa,which has an identical life-history, 
but 1s characterized in the cercarian and sexual stages by its spinose body. 
An Acarus or Mite (Philodromus limucum 
Jenyns) infests this and other species, and is 
very frequently seen nimbly running over the 
body of the animal. According to Réaumur, 
they often inhabit the intestinal canal, and 
take every opportunity to arrive there; but 
Dr. Jenyns considered their natural habitat 
to be the pulmonary cavity. 
Klossia, a genus of Gregarinide, is parasitic 
within the enlarged epithelial kidney cells of PDs: : 
this species, and in such position is filled Jenyne SB eh cose eee 
with glycogen granules. of Helix nemoratis, etc. 
Osmia bicolor, a species of solitary bee, has been observed at Wotton- 
under-Edge, making its nidus within the shells of this species. 
Geological Distribution.— Helix nemorulis is recorded as found in 
this country from the Coralline Crag up to the most modern deposits. On 
the continent it has been found in South France as low as the Miocene. 
Miocene.—Abbe Dupuy records it as fossilized in all the lacustrine 
deposits in the north-east of the department of the Gers. At Sansan it 
occurs in a pocket of “terre marneuse” enclosed in the limestone; it has 
also occurred at ‘l'ougac, Mirande, Idrac, and Durand, but usually only in 
the form of casts. Dr. Paladilhe notes the finding of a probable specimen 
of the species enclosed in a block of Molasse at ‘St. Bauzille de la Sylve, 
between Gignac and Pouget. 
