MOULTING HABITS OF SPIDERS. 109 
Waldemar Wagner, the Russian savant, whose skillful and patient researches 
have heretofore been quoted. I shall draw chiefly upon his work “La 
Mue des Araignées” for the material which it serves me to pre- 
Physio- sent here. For full information the student is referred to Mr. 
Moule Wagner’s paper. It will sufficiently answer the purpose to give 
oulting 
Changes. ® general notice of the developmetit of the process, and to illus- 
trate these by quoting somewhat in detail, in the case of several 
organs, the genesis of the new skin and the rejection of the old. 
Ordinarily the matrix of spiders presents a layer of protoplasm with 
numberless cells. This is colored equally throughout, the cell, as usual, 
being more, the plasma less, intensely colored. As the moulting time 
approaches one ceases to observe this equality of coloration; the superior 
layers next the old cuticle are colored more and more feebly; and finally, 
at the moment when the contingent layer ceases to be colored and loses 
its granulation, and when, consequently, we may rightly consider it as trans- 
formed into a chitinogenous layer, then the future tegument begins slowly 
to separate from the old. 
As the new skin is retracted from the old cuticle the interval thus 
formed is filled with liquid, in small quantity at first, but gradually 
._ increased with the enlargement of 9¢ ... AWWA 
ee the cavity. The new tegument nt... BRFBRSESESE 
increases rapidly ; within the ceph- ye .. 2g" Tp yee 
alothorax, not being able to have full exten- wen ages 
sion, it forms many folds (Fig. 67, fin.t), MM fmt folds Sine ie ee 
destroying thereby the layer of the old tegument under the old (0.t). 
cuticle, which is drawn from it, and from which it is disengaged little by 
little. On the abdomen one does not observe these foldings of the new 
skin, because the old is there so pliable that it does not impede the growth 
of the new. At the moment when the new hairs are completely formed 
there remain of the old skin, separated from the new, only the tubes which 
serve as sheaths for the new hairs; and, on the day of the moult or the 
day before, these sheaths are destroyed, and the liquid underneath the 
tegument disappears, 
The moult of the eyes takes place simultaneously with the other organs; 
the matrix in process of growth insinuates itself between the vitreous body 
and the preretinal envelope, the cells of which are in that way 
reed upward and lose their regular form. The moulting of all 
the eight eyes does not take place at once, but probably at differ- 
ent times. With Attus terrebratus, at least, the lateral eyes are the first to 
end their moult. For a period longer or shorter before the rejection of the 
old skin, according to the stage of development, spiders lose their sight, 
and after the moult vision is not restored all at once.: 
During the moulting of the lungs breathing is difficult, but the time 
occupied therein is short. Two of the three layers which compose the 
Byes and i " 
Lungs. 
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