CHAPTER XI. 
ACEPHALOUS MOLLUSCA. 
“ Sigillatim mortales, cunctum perpetui.” 
Apuleius. 
"Ur 
' reach here the true Mollusca. The transition condition of the 
°"u sooida has prepared us the better to comprehend the nature and 
dJ1 te of the molluscs, properly so called. 
■file name Mollusca indicates the characters which most struck the 
atlc ients : they are soft — in Latin, nolle s ; then- flesh is cold, humid, 
! U d viscous. In consequence of their very softness, they are generally 
Wished with an apparatus of defence or protection, in the shape of 
Ca lcareous cuirass, called a shell or test. According to the species this 
is a coat of mail, a buckler, or a tower. The mollusc is thus 
^ed and defended against all attacks from without, nearly after the 
' ltUl er of a knight of the middle ages ; only the knight was not 
j , e shut up in his armour, while the mollusc is attached to it by 
f ^soluble organic bonds. “ Such a life and such a habitation !” 
ys Michelet. “ In no other creature is there the same identity 
'tween the inhabitant and the nest. Drawn from its own substance, 
® ef hfice is the continuation of its fleshy mantle. It follows its form 
tints. The architect has communicated its own substance to the 
e dific e . 
; ,^ le shell of the Mollusca has been variously appreciated bynatural- 
o ( . y ."We might regard the shell as the bone of the animal which 
^ it,” says a celebrated French naturalist ; and then gives ex- 
^ e ssion to a very different view. “ We may say as a general thesis 
°ut ^ es ^ acecms molluscs are animals with whom ossification is thrown 
011 the external surface in place of the interior, as in the Mam- 
