™ 
334 HELIX HORTENSIS. 
in breadth, but capable of much greater extension; the head was of a 
reddish colour, the remaining segments except the last being yellowish 
above, each with a rectangular black or blackish mark, separated into two 
by the pale longitudinal mid-dorsal streak ; the fifth to the twelfth seg- 
ments each bore a pair of large and triangular creamy-white tubercles 
armed with long spiny brown sete, a series of which also defend the 
spiracles. ‘lhe underside was creamy-white, with two black streaks on each 
segment. ‘lhe thirteenth segment is an ambulatory stump and bears a 
backwardly-directed bifid tubercle, set with long hairs on the upper side. 
The larva was very active in its movements, and became very excited 
immediately on perceiving the presence of the //eliz, which had been 
placed in the receptacle with it, mounting at once upon the shell, and 
bending its body round to insert the head and anterior segments into the 
shell at the base of the columella. 
‘he snail on feeling the intrusion immediately withdrew into its shell, 
drawing in with its body still more of the larva. In its further attempts 
to squeeze out and get rid of its enemy, the snail repeatedly and quickly 
emerged from and retreated within its shell, but this was unavailing, as 
its tender body shrunk from contact with the spiny sete of the larva, 
which also kept from the spiracles the slime thrown out by the snail, 
while at each retraction of the body the larva pressed further and still 
further within the shell, until the snail eventually gave up the struggle and 
became quiescent. 
The larva then at once began devouring its victim, whose juices could 
be distinctly seen passing down its gullet. In about four days the snail 
was almost wholly consumed, the body of the larva having become 
distended to an enormous extent, and, except for a slight occasional 
contraction of the segments, it remained motionless until May 19th of the 
following year, when it passed quickly through the pupa state, emerging 
as a fine female beetle on the following day. 
The Philodromus limacum? is also common on this species, and would 
appear to be very hardy and indifferent to cold, as they have been 
observed in winter imprisoned behind the epiphragm of a hibernating 
animal, running about quite actively within the restricted space. 
The Distomum caudatum of Loos (referred to on p. 282) is said by 
Prof. Blochmann to pass its sexually mature stage in the intestinal canal 
of the hedgehog, and to have Helix hortensis for its imtermediate host, 
gaining access to the snail in its early and active larval stage, and lodging 
within the kidney during the cercarian period, completing its ‘development 
within the hedgehog when it has devoured the snail. 
Conchophthirius steenstrupii Stein, a Protozoan, belonging to the Pura- 
maciidw, is also recorded as a 
minute ecto-parasite on the body 
of the present and other species, 
feeding upon the mucus or slime. 
It is of a depressed broadly-oval 
shape, with the widely infundibular Ae i308. 
fossa placed near the anterior end, Conckpl sinus Giekeeapie Sicha OER 
the body being clothed with long dorsal and lateral aspects, x 150 (after Quennerstedt). 
and delicate cilia; and the con- — F'¢-395—Dorsalaspect. Fic. 396—Lateralaspect. 
tractile vesicle spherical in shape and subcentral in position. 
1 Monog. i., p. 423, f. 738. 
