EESPIRATOEY ORGANS IN ARANEA^. 
7 
After hatching the embryos remain motionless for five to 
sis days or even a little longer before the first post-embryonic 
moult takes place, after which the young spiders acquire the 
use of their limbs. They are still, however, in a very im- 
perfect condition, especially as regards the eyes. They remain 
in the cocoons until after the second moult, which takes place 
sixteen to seventeen days after the first. The young spiders 
then emerge in a perfect condition, with fully-developed eyes, 
and have also acquired the definite shape of the adult. ^ 
The entire development, therefore, takes from about thirty- 
seven to forty days, less than half of which number is spent 
within the e"sr-shell. 
Treatment. — The preserving reagent upon which I mostly 
relied was a hot concentrated alcoholic solution of corrosive 
sublimate, which 1 make use of in the following manner : 
A quantity of sublimate is placed in a small, loosely corked, 
boiling fiask with sotne alcohol of 70 per cent, and heated 
over a flame with constant shaking until the alcohol begins 
to boil. Home of the concentrated solution is then poured 
into a small tube of about 3 c.cm. capacity, which is imme- 
diately corked and suspended by a string in a basin of water 
heated to 80°C.“ A few eggs are now dropped in and 
removed almost immediately afterwards by means of a thin 
glass rod, which is flattened at one end and here bent at 
right angles to form a scoop large enough to take out one 
egg at a tiine.^ The sublimate will probably be precipitated 
during the latter operation, but that does not matter. The 
eggs are then placed in G3 per cent, alcohol (70 percent, will 
Heider {’92, jj. 588). Later oii I found a similar black tooth on the base 
of each pedipalp in the embryo of a Tetrapneunionous spider (Harpac- 
tira atra) from Cape Town. • 
' Similar phases occur in the development of all other Dipneunionous 
spiders which I have examined. 
^ A temperature of 70° has much the same effect. 
^ It sometimes happens that the egg-shell bursts, in which case the 
embi-yo is destroyed by the violent action of the reagent. As a rule, 
however, it remains intact and only just sufficient reagent penetrates to 
preserve the embryo. 
