ARION ATER. zal 
constituted by a tricuspid median tooth, flanked by about twenty-six rows of lateral 
teeth, which though obscurely tricuspidate adjoining the median row, gradually 
become distinctly bicuspid ; the marginal teeth are mainly bicuspid ; the mesocone 
increasing vastly in size and importance, the endocone totally disappearing, and the 
ectocone “diminishing greatly until in the extreme marginals it also becomes totally 
lost, and the teeth are simply aculeate. 
The formula of a Bali SUSCMNE: collected by Mr. J. R. Redding, is 
+35 +3 e+$5 42! x NGO == 94760: 
Reproduction: oe Derelopnient. —The congress of this species is 
preceded by the prolonged circular procession pre- 
viously described, and which may be continued for 
an hour or more, the head of each animal resting 
upon the tail of its partner during the promenade, 
and both slowly devouring the mucus exuded by 
the caudal gland and by the body cells. he con- 
gress is not of long duration, the union being 
effected by the extrusion of the genital cloaca, 
especially of the oviduct, ete., which constitute 
the intromittent organ, the seminal element being 
mutually transferred by means of the denticulate 
spermatophores. F Fic. 201.—Spermatophore 
This species, however, sometimes reproduces of 4. ater v. ru/a, enlarged 
parthenogenetically, as Mr. F. W. Wotton has Soe ee 
reared individuals in captivity, which though kept strictly isolated almost 
from birth, produced fertile eggs. 
The eggs, which are excluded in from four to five weeks after the union 
has taken place, are about five mill. long, and four mill. in diameter, some- 
what oval in shape, thick skinned, and semipellucid when fresh, but quickly 
changing to an opaque-white, a circumstance ascribed to the innumerable 
calcareous particles in the outer envelope, this calcification tallying with the 
copious deposit of lime in the arterial walls. They are deposited in vast 
numbers at almost all seasons of the year—many clusters have been found 
as early as January in this country-—under stones, old wood, dead leaves, 
at roots of plants, etc., usually in clusters of from twenty to fifty, or more; 
they hatch in from thirty to fifty days, according to the weather. 
The young when hatched are usually unicolorous, but apparently vary 
in shade, in different countries; in Germany, Scandinavia, and North 
Central Europe they are said to be pale yellow or greenish-white, but 
more inclined to blackish in the mountain regions, while- in the warm 
plains and in the south they are reddish, and in England frequently of a 
yellowish or greenish-grey, with slightly darker shield and head, often closely 
conforming in tint to the fallen faded leaves of autumn. In many cases lateral 
banding develops during growth, which may occasionally, especially near 
the outskirts of its range, persist in adult life, but usually the darker 
markings become clouded over and the unicolorous stage is reached. 
Mr. W. A. Gain has carefully chronicled the varied changes undergone 
by animals during growth. At eighteen mill. in length they were almost 
without exception of a greenish-yellow tint, with greyish lies and mark- 
ings, but this m some cases would gradually but quickly change to a 
brownish tint, the tint gradually becoming a rich brown with dark lateral 
bands on body and shield, and eventually when full grown presenting a 
deep brown back and shield, with black-brown sides and orange fringe. 
Other specimens, apparently quite similar when young, may become very 
differently coloured as adults. 
vin 
