the members gradually free themselves from their sheaths, commencing 
posteriorly. This is the ordinary mode, but there are exceptions. 
The Tarantula {Trochosa singoriensis) passes through four moultings 
before commencing an independent life, and passes through several 
others before it attains full size. The author describes the peculiarities 
of certain genera. The hairs of an arachnid are produced from the 
lowest stratum of the cuticle, which rises in the form of a tube and 
perforates the upper layers, and are unicellular. The moulting of 
the eyes is confined to a comparatively sudden increase, the retina 
withdrawing itself from its envelopes. Sight is lost during the pro- 
cess, but it does not seem that that process in simultaneous in all the 
eyes. The moulting of the lungs is accomplished at once, and breath- 
ing is difficult during its duration, but the time occupied is short. 
Two of the three layers which compose the tracheae are lost during 
moulting. The linings of the silk glands of the arachnids are shed, the 
broken parts of the old tubes remaining among the silk by which the 
arachnid is attached during the moult, and all glands formed by 
ectodermic invagination also lose their linings. The pharynx, oeso- 
phagus, and rectum take part, in the moult, as do also the tendons, 
especially of the miiscles of the limbs, the matrix growing around the 
old tendon and forming a new one, while the old one atrophies and is 
cast away with the tegument. During the operation of moulting the 
number of spherical corpuscles, which usually is only three to four 
per cent, of the total number of corpuscles, increa.ses to ten per cent., 
almost all the colored corpuscles being transformed into spheres. 
Want of movement during the process seems to be one, but not the 
sole, cause of this change in the condition of the blood, and it must be 
remembered that a development of all the internal parts of the body 
takes place at the moulting period, so that the casting off of the tegu- 
ments, etc., is really but a secondary act. 
Some Arachnida seem to pass through the entire process of moulting 
ea.sily, and take little or no precaution (many Thomisidse, e.g.'), while 
others, as many Attidas and the adult Trochosa, take all possible pre- 
cautions to shelter themselves from danger, since after the rejection of 
the tegument they are so feeble that an insignificant foe can master 
them. If a limb be detached immediately after a moult, it is renewed 
before the next moult, but if the loss takes place a short time before 
moulting, only a papilla is formed in the interval. Increased time is 
occupied in the moulting of adult individuals, and spiders do not 
moult in winter nor when deprived of nourishment for a considerable 
