120 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
say, until complete sexual maturity. After that period no lost organ or 
part thereof will be renewed, no matter how long thereafter the spider may 
live. The function is thus evidently designed to favor the maturity of the 
species and so insure its continuance. 
ONT, 
As has been said, the regeneration of lost organs is the result of two 
processes, equally important and interesting, the atrophy of the old tissues 
and the formation of new. If one cuts off a spider’s foot all the 
eet e tissues which fill up the remainder of the limb disappear, and 
Oo 
TY : F ; 5 
Seger: oped within the cavity of the joint from which the old tissues 
have been atrophied. 
Immediately after the operation Nature begins to cover up the wound, 
the blood cells form a thick cellular mass, which in the course of three 
days is formed into a 
hard, dark scab, which 
serves*as a stopple to 
the open wound. This 
is shown at Fig. 80, 
and a longitudinal sec- 
tion at Fig. 81. In 
the latter, one sees the 
Fic. 80. View of healed stump of a spider’s amputated limb. Fic. 81. Lon- old cuticle (ct) united 
gitudinal section of same; ctx, the cicatrix; ct, cuticle; mss, granular 7 
mass next the cicatrix ; ch.c, chitinized cells; b.c.a., amceboid blood cells; with the scab, and the 
b.c.r., red blood cells. chitinous membrane 
under which is the row of deep cells of the matrix (Mtx). Immediately 
under the surface of the cicatrix lies a mass (mss) of unstratified 
ei aoe granular matter, next to which is a nest of cells arranged in 
Gicatrix, TOWS one above another, gradually diminishing in length and 
receding into the cavity beneath. Of these the upper tier are 
“chitinized” cells (ch.c), and the remainder blood cor- 0 ctx B 
puscles, both red (b.c.r) and amoeboid (b.c.a). The transi- Ameo 
tion or destruction of these cells, and their metamorphosis 
into the structureless mass of the covering cicatrix, is 
accomplished gradually. 
Now the matrix, which alone of all the tissues does 
not undergo entire degeneration, begins to retract little by 
little from the cuticle, thus parting from the ,,, 9 peneicaee a 
eae cicatrix. It commences at the top of the joint stump when matrix, 
Cita Within whose cavity its ends are approximated. M‘; begins to re- 
Matrix. tract ; A, B, lower and 
It is withdrawn more and more, forming above _ upper cavities; 0, ori- 
° - fi ‘ 
the old tissues a sort of cupola, to use Wagner’s word. ide ee Nae 
Fig, 82. 
simultaneously a new organ is originated and completely devel- _ 
