MOULTING HABITS OF SPIDERS. 113 
these there is a large number of points of immediate insertion of the 
muscles upon the cuticle without thickening of the chitine at that point. 
Like conformations are observed upon the dorsal face of the abdomen. 
These are near the local thickenings of the chitine at the points of inser- 
tion of the dorso-ventral muscles, 
and in the interval comprised be- 
tween the lines of the local thick- 
enings upon the dorsal face and the 
lateral line of thickenings. (Fig. 
74, Nos. 17 and 89.) 
An examination of rejected teg- 
uments shows the existence of two 
forms of points of insertion, which 
differ in structure and size. One 
presents a thickening, more or less 
considerable, of a sculpture tuber- 
culous upon the exterior (Fig. 75), 
and having a row of cells and walls 
more or less thick upon the inte- 
rior. (Fig. 76.) Each of these cells 
serves for a point of immediate in- 
sertion upon a fasciculus of muscles, 
so that the number of cells indicates 
the number of fasciculi. The other e : ; 
: - : : Fic. 74. (After Wagner.) Rejected tegument of spider’s 
mode of immediate insertion of the abdomen, ventral part, showing points for muscular 
muscles shows no thickenings of the attachment ; 0, genital orifice ; pr, pores; 1-16, sixteen 
ce pairs of points of insertion of two median series of 
chitine ; but one observes at these muscles; 17-89, twenty-three pairs of points of inser- 
points upon the tegument certain tion for two lateral series ; pou, gills. 
linear thickenings, hardly distinct, which indicate the limits of the point 
of insertion of the muscles and of each of the fibres taking part. 
One can hardly fail to note that the arrangement of these points of 
attachment indicates in a general way, and indeed with tolerable accuracy, 
the outlines of the markings which 
ALG distinguish these animals. For the 
eget, CO most part these are so grouped as 
Veal =ae: to form a folium or rude figure of 
(uaitha a leaf with various irregularities, as 
pag ke Hip: 7a scallops and dentations, upon the 
Points OF INSERTION OF DoRSO-VENTRAL MUSCLES. hi * 
: ickenings first de- 
Fic. 75. Exterior tuberculous sculpture, with thick- edge The thicke ng st s 
ening. Fic. 76. Interior cells, without thickening. scribed are always of a yellow col- 
iabey BREE) or, more or less intense; a color 
which is the dominant one in nearly all families of spiders showing decided 
hues. In the second form of attachment the cuticle is colorless and trans- 
parent. In both cases the skin above the points of insertion is without 
