4 GENUS TESTACELLA. 
The LINGUAL SHEATH white and gristly, exhibiting externally along its 
left upper surface a distinct longitudinal suture or seam on opposite sides 
of which, at the hinder end, the “paired constituents of the retractors are 
affixed; the enormous development 
of the retractors is in strict correlation 
with the nature of their food, as to 
overcome the highly muscular and 
struggling earthworms demands a pre- . “ 
dominating antagonism ; TENTACULAR i ‘ 
RETRACTORS very long and quite inde- Fic. 5.—Hinder end of lingual sheath of 7. 
pendent of the phary neeal group, and mauge?, from Hayle, Cornwall, x 4, showing the 
of each other, with widely separated Beg al aa ea 
points of attachment to the integument, differing thus from the Limaces, 
and forming with Asion the group richorhiza.? 
The REPRODUCTIVE ORGANS are comparatively simple, varying somewhat 
not only in the relative proportions of their various parts, but also as in 
other groups increasing vastly in size at the approach of the breeding sea- 
son; the OVOTESTIS small, imbedded within the large digestive cland ; 
the HERMAPHRODITE DUCT closely convoluted and entering the large and 
yellowish albumen gland about its middle ; ovrpuct with broad, ample folds, 
sugeestive of large egos, partially doubled upon itself, owing to the high 
attachment of spermathec &; PENIS SHEATH only moderately developed; no 
mucus glands; ATRIUM short and narrow; penis and vagina separated by 
the right tentacular retractor. 
Reproduction and Development.—In mild weather, especially in 
spring and autumn, the pairing takes place, the tentacles being retracted 
during the process, which occupies four or five hours. Five or six days 
afterwards, ten or more eggs are deposited within the underground galleries, 
sometimes a yard or more beneath the surface. ‘The eggs are oval and 
white, somewhat acuminate at the ends, and although enclosed by a hard, 
calcareous shell, explode with a perceptible noise when removed from the 
ground and placed upon the hand or m a warm place, but, according to 
Faure-Biguet, they may be preserved if plunged at once into boiling water. 
The eges hatch in from ten to thirty-five days, according to the species 
and the prevailing temperature, the young at once entering upon a preda- 
tory life, devouring young earthworms and the minute white threadworms 
which live beneath decaying vegetation ; they usually become adult in about 
eighteen months, and may attain five or six years of age. 
Food and Habits.—'hey are predacious and very voracious and not 
only prey upon worms, but will also devour slugs, snails, centipedes, and 
even small individuals of their own kind, although, according to Gassies, 
they will not eat dead animals, and even decline fresh worms which have 
been chopped up to feed them, Bouillet, however, records that chopped 
worms are devoured by the Zestacella when laid as bait on the ground. 
The prey is seized by a rapid protrusion of the odontophore, the worm be- 
coming impaled upon the multitude of barbed and aculeate teeth which 
divaricate during protrusion; the radula is then retracted and the worm or 
other prey is oradually engulphed in the maw of its enemy, but so slowly in 
some cases that one end of a worm may have become digested within the 
stomach while the other end still alive projects from the mouth. / When 
gorged with food the animal becomes lethargic and contracted, but if disturbed 
during a meal they will often disgorge the prey they may be consuming. 
1 Monog. i., p. 344, f, 638, 
