138 Beautiful Shells. 
most destructive of molluscous animals, devouring 
the roots of plants as well as their leaves. It is 
bisexual and very prolific, breeding several times 
a year; and Chautereaux counted three hundred 
and eighty eggs deposited by two individuals be- 
twixt April and November, laying from thirty to 
seventy at a time. They rapidly increase in size, 
and reach maturity in three months, although they 
probably begin to lay eggs in about two. The D. 
flavus, or variegatus (for although the lower surface 
be yellowish-grey, the upper is thickly and irre- 
eularly-spotted blackish brown), has a limpid slime, 
but secretes, when irritated, a thicker bluish-white 
mucus. On reaching any twig or place where there 
occurs a difficulty of proceeding, it allows itself to 
drop or be slowly lowered by its thread of adhesive 
mucus, which at length gives way. This is the 
slug which is found under damp turf and stones, 
beside walls and among plants. It is twice the size 
of the field slug, being from three to four and 
sometimes even five inches long. Mr. H. J. Lowe 
says it is best known as the cellar slug, and is 
in such situations gregarious. The tree slug (DL. 
arborum) is greyish, with marbled side-stripes, and 
a dusky band along the back. It feeds upon wood 
and affects decaying trees, whence it uses its 
