No. 407.] A SINGULAR ARACHNID. 847 
“1. The mouth of the Palpigradi (as we have already pointed 
out above) differs from that of all other Arachnida, nay, from 
that of almost all other Condylopods, in being formed exclu- . 
sively by the labrum and the hypostoma. And even if Kæne- 
nia did not offer other characteristics, this circumstance would, 
to our eyes, be sufficient to set it aside as an independent 
order. 
“2. The antenna (chelicerze) of the Palpigradi are three- 
jointed, and the two distal joints form a pair of pinchers with 
horizontal movement of the third joint against the prolongation 
of the second. In this structural feature Koenenia agrees with 
the Opiliones and Scorpiones, and differs most decisively from 
the Pedipalpi, in which the antennz are two-jointed and do not 
form real pinchers. 
“3. The five remaining pairs of limbs are similar in all the 
most essential features, as none of the anterior three pairs 
(second, third, and fourth) are provided with maxillary lobes 
which help to form the mouth, but are developed exclusively as 
organs of movement, like the two posterior pairs of limbs which 
in all arachnids, where they are found at all, are merely instru- 
ments of movement. Therefore the foot (tarsus~s. /a7.) in all 
five pairs is divided into a metatarsus and a tarsus (s. str.). In 
the four posterior pairs of limbs patella and tibia are well devel- 
oped, while in the second pair only one single joint is present. 
“4. The abdomen consists of eleven segments, which arenot —— 
divided into dorsal and ventral plates. ue the Pedipalpi r e 
consists of twelve segments, which ( 
ones in the Uropygi) are divided into a i dorsal and a ventral v 
plate. (Only in Amblypygi and Tartarides. the first ventral E Et 
plate is very sparingly chitinized.)" . 
The relationship of Koenenia to other arachnids eh the po 
central group of the Pedipalpi is comparable to the relationship 
of the Thysanura (Campodea, Iapyx, Lepisma, eg.) to other — 
insect orders through the Orthoptera (including Dermaptera). 
In fact, Koenenia, with its simple and generalized. organization, | 
reminds one of such phylogenetically important types as Poly- 
=~ Berdius, Campodea, Scolopendrella, Amphioxus, : and Myxine. : 
de ied these animals ] it sn combines i in its ipon 
& 
