HANSEN AND SÖRENSEN: THE ORDER PALPIGRADI. 231 
processes, which, in our opinion (agreeing with Grassı’s previously 
stated view) indicates their function as instruments of sense. The 
foremost of these couples (fig. 5; st in figg. 1, 4 and 7) is situa- 
ted in the median line of the body and on the front of the 
head close above the first pair of limbs; it consists. of two flat 
lancet-shaped bodies which by a common basal part are attached 
to the head, against which they are pressed (fig. 4). The second 
couple forms two blades (fig. 6; s? in figg. 1 and 3), which are 
placed close up to the sides of the head above the coxæ of the 
second pair of limbs, and which — though deviating somewhat 
in shape — in quality very much resemble the first couple of 
blades; they turn — at least when in repose — horizontally 
forward and outward. As they are articulated to the head, it 
is not unlikely that they can move. — Morphologically they are 
hairs !?, 
The Zartarides being the group of Arachnida to which the 
Koenenia are nearest akin, we have examined Schzzonotus crasst- 
caudatus Camper. and Sch. Szmonzs n. sp. (a description of which 
will be published later). The above-mentioned sensory hairs are 
found neither in the former, which is quite blind, nor in the 
latter, which has an »eye-spot». 
Tactile hairs have been found by us as well as by Grassi 
(who is inclined to consider them as auditory organs) only on 
the third pair of limbs: one on the anterior and one on the 
posterior side of the first metatarsal (sixth) joint, two on the 
anterior side of the second metatarsal (seventh) joint, one on the 
anterior side of the fourth metatarsal (ninth) joint, and one on the 
front side on the second tarsal (eleventh) joint. They are much 
longer than the others, very thin and nearly of equal thickness 
from the base to the point!*. The circumstance that this (third) 
pair of limbs are so much longer than the others, and that they 
‘* Grassi, no doubt a little thoughtlessly, has taken them for antennæ 
(antenne interne and esterne). We shall not enter upon any criticism of this 
notion. 
18 We refer to a paper by one of us about these and other organs in 
other Arachnida namely: H. J. HANSEN: Organs and Characters in different 
Orders of Arachnids (Entom. Meddel. B. IV, Kjöbenhavn 1893--1894, pp. 
137—242, Tab. II—V). 
