196 ARION SUBFUSCUS. 
SALIVARY GLANDS are yellowish, and frequently form a collar round the esophagus, 
uniting above and embracing the anterior part of the crop, like turned up moustaches ; 
the SALIVARY DUCTS white; CROP dusky-buff in colour, and distinctly wrinkled 
longitudinally ; DIGESTIVE GLAND dark brown. 
The MANDIBLE or jaw is about 14 mill. broad and half mill. wide, crescentic 
in shape, with rather acutely-rounded ends, arcuate from 
front to back, but somewhat flexible, of a deep amber- 
brown colour along the lower or cutting-edge, gradually 
blending with the paler tint of the upper moity; the 
anterior surface bears ten to sixteen broad, rounded ribs, 
which show well-marked vertical strive, and strongly 
crenulate the upper margin, and sometimes denticulate 
the lower margin also, especially near the centre, simu- 
lating a rostrum or beak; the interspaces between the 
projecting ribs is of perceptibly more delicate texture and shows the horizontal 
wavy striation most perceptibly. 
The LINGUAL MEMBRANE is oblong in shape, about 44 mill. long and two mill. 
wide, and composed of about 140 slightly curved transverse rows of closely-set teeth, 
which appreciably diminish in size at the outer margin ; each row is composed of a 
tricuspid median tooth, with about fifteen obscurely tricuspidate laterals, the 
endocone gradually degenerating, and the ectocone acquiring correspondingly 
greater strength and importance ; the marginal teeth are about thirty in number 
at each side, and are essentially and strongly bicuspidate, constituted by the well- 
developed mesocone and ectocone. 
SHARIA RANE 
Fic. 215.—Representative denticles from a transverse row of the lingual teeth of 4. sudfuscus, X 180. 
The animal collected by Mr. C. Ashford, and the palate prepared by Mr. J. W. Neville. 
The formula of a Christchurch specimen collected by Mr. C. Ashford is 
BO 4 45 44445 432 x 140 = 12,740. 
Reproduction and Development.—The congress of this species is 
probably marked by the same blandishments and circular procession as in 
Arion ater, yet although it breeds freely in confinement, no definite 
observations are on record. The eggs, which are chiefly deposited in the 
late summer and autumn months, are oval in shape, averaging 3 mill. long 
by 24 mill. in diameter, of a dusky white, but sometimes amber or dull 
primrose colour, or even pale green, translucent, and much clearer than 
those of A. ater, slightly granulate on the surface, and connected together 
by a colourless or yellowish mucus: they are laid upon or beneath the 
ground in clusters varying in number from about twenty to sixty or more. 
The young apparently pass through the winter in the juvenile stage, as all 
the specimens observed by Dr. Scharff, even as late as May, were immature. 
The young, according to Clessin, differ from those of A. ater, which are 
almost invariably of an uniform light yellow or greenish colour, as they are 
usually darkly coloured, and only pale to some extent with age. 
Food and Habits.— Arion subfuscus is naturally very partial to fungi, 
aud has been observed to frequent and feed upon Russula fuscatu, as well 
as the poisonous Agaricus muscarius. In summer it has been observed 
feeding upon the leaves of Leontodon wutumnale, but in autumn they 
display a great partiality for fungi. 
In captivity, according to Mr. Wallis Kew, they eat bread and lettuce 
freely, the decaying leaves of the Deadly Nightshade (Solanum dulcamara) 
are also eaten, as well as dead slugs of their own or other species. The 
fungus Phallus impudicus was also offered and greedily devoured, but the 
annals feeding upon it died soon afterwards. 
Fic. 214.—Mandible or jaw 
of Arion subfuscus, X 15. 
(Christchurch, Mr. Ashford). 
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