212 ARION HORTENSIS. 
imperceptibly into the vas deferens, it secretes the short thick SPERMATOPHORE, 
which has a smooth, thin envelope, without the serrated crest so conspicuous in 
Arion ater and A. subfuscus ; the SPERMATHECA is globular, variable in colour, and 
attached by its crown to the base of the OVISPERMATODUCT, the stem is short 
and thick ; ATRIUM with a well-defined ochreous vestibular gland; the GENITAL 
RETRACTOR arises from the dorsum, behind the kidney, but soon bifureates, the 
extremities becoming fixed to the stem of the spermatheca and the upper third of 
the free ovidnet. 
~ 
Fi. 223. Fic. 224. Fic. 225. 
Fic. 223.—Reproductive organs of Avion hortensts Fér., X 2. (Christchurch, S. Hants). 
Fic. 224.—Spermatophore of Avion hortensis Fér., Leipzic, greatly enlarged (from an original 
drawing by Dr. Simroth). 
Fic. 225,—Alimentary canal of Avion hortensis Fér., X 2. 
ot. ovotestis ; A.d. hermaphrodite duct ; 4. prostate; v.d. vas deferens ; ef. epiphallus ; a.g. 
albumen gland ; ov. sacculated or glandular oviduct ; sf. spermatheca ; vag. vagina; az. atrium; 
v.g. vestibular gland ; ».2. retractor muscles attached to spermatheca and free oviduct. 
The MANDIBLE or jaw is about a mill. broad, and about half-a-mill. wide, with 
narrower but somewhat bluntly rounded ends, strongly 
arcuate from front to back, of an amber colour, with 
about ten vertical ribs or thickenings, apparently 
formed by overlappings of the substance of the jaw, 
which crenulate the upper margin and sometimes the 
lower margin also; the darker ribs and the clearer mS ae Ft of 
interstitial spaces show distinet vertical strive; at 470% 2o7~ensis, x 20. rist- 
about one chic of the width of the jaw, a dark line CeUr Sp ants Me Ge 
runs parallel with the cutting margin, showing the point of origin of the elasma, 
which extends on to the roof of the buccal cavity. 
The LINGUAL MEMBRANE is about three mill. long and one mill. wide, consti- 
tuted by about 116 somewhat curved transverse rows of teeth, which diminish 
regularly in size to the margin of the membrane. The transverse rows are each 
composed of a strongly tricuspid median tooth, the strong yet somewhat slender 
mesocone, With distinct accessory lateral cutting expansions ; the lateral teeth are 
about ten in number, obscurely tricuspid, but the endoconie cutting point is lost, 
the mesocone shewing the side expansions; the marginals are unicuspid, showing 
the powerful mesocone only, but towards the margin an ectoconie cutting point 
again becomes distinctly perceptible, while the few extreme marginals still retain 
their embryonie character. 
35 
Y 1.29 20 
ja) 
35 
(7. {2 6. L m 1 6 12 17 20 30. ) 
\ V 
VU A Meat Wy vr 
Fic. 227.—Representative denticles from a transverse row of the lingual teeth of 4. sub/fuscus, 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 
TH+ H+ ES+et+SSt+t34+7 x 116=8,468. 
