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on the 4th pair and on all the legs of the female. Seen 
even under a strong magnifying-glass they appear to be 
but very small, clavated hairs, but making use of the 
microscope it is evident that each »hair« consists of 
fewer or several very fine hairs, collected at the basis 
in a compact bunch, issuing from a hollow in the centre 
of a small eminence (Tab. IV, fig. 8 and fig. 9). These 
bunches are placed in 2 or 3 irregular longitudinal rows. 
The single hairs are slightly dilated near the tip and 
they split in several rather short, pointed branches (fig. 
9). The integument of the leg is thick, but on a properly 
cleaned specimen the hairs can be seen passing through 
it, and exceedingly small, partly clear chitinous forma- 
tions issue from the basis of the hairs. By dissecting 
the leg it is evident that from the basis of each bunch 
there issues a kind of radiation of the surrounding, soft 
tissue and that this radiation takes up almost 1/; of the 
diameter of the leg; but I have not entered into the 
histological study of this tissue. The chances are that 
the whole formation is a kind of sense-organ; it being 
stricking, however, that these hairs are wanting in both 
sexes of Phal. cornutum L. and in the other Phalan- 
gioide living in Denmark. 
C. Supplementary Spiracles on the Legs. 
In the larger species of the genus Phalangium is 
easily seen a small, dark ring on the posterior side of 
tibia of all 4 pairs of legs close to the basis (Tab. IV, 
fig. 1, a), and a smaller ring is found on the upper side 
of tibia a little in front of the tip (fig. 1, b). It is proved 
by closer examination that these rings are spiracles 
Fig. 4 and the diagrammatic fig. 3 show the structure 
of the proximal spiracles. The exterior integument (a) 
is towering slightly up, having in the centre a round 
