846 THE AMERICAN NATURALIST. | [Vor. XXXIV. 
animal and its unmistakable resemblance to Thelyphonus, the 
whip-tailed scorpion. Without differing to an appreciable 
extent from Grassi in his conception of the taxonomic impor- 
tance of Koenenia, Thorell! has seen fit to change the name 
of the new order to Palpigradi. Hansen and Sörensen have 
adopted this namé and have abandoned Grassi's. It would 
seem, however, that notwithstanding the aptness and brevity 
of Thorell's name, it can hardly be accepted without violating 
the law of priority in nomenclature. 
Hansen and Sórensen make it clear that the Microthely- 
phonida are far removed from all the other orders of Arachnida, 
excepting the Pedipalpi. On this subject I cannot do better 
than to quote zz extenso the opinion of these competent arach- 
nologists ? : 
* While it is easy enough to show differences between 
Palpigradi and Scorpiones, Chelonethi, Solifugz, Opiliones, 
J Aranez, and Acari, we confess that we should find great diffi- 
culty in detecting resemblances to these orders, except in the 
fact that they are all arachnids. Though, indeed, the order 
Pedipalpi i is poor in species, its two suborders, Amblypygi (with 
the family Phrynoide) and Uropygi (with its tribes Oxopoei — 
the family Thelyphonoidz, and Tartarides), exhibit great mutual . 
differences, for instance, in the structure of the mouth. And, 
indeed, it is the most central of the orders of Arachnida ; 
through Amblypygi it reveals decided affinity with Aranëæ; — 
through Tartarides with Palpigradi ; and through Oxopoei, to 
. a minor degree, with Scorpiones and Chelonethi. As stated 
. by Thorell several years ago, Opiliones and Acari are closely . 
related to each other, but we confess that these two, as well as |. 
the Solifugæ, must still be said to stand far apart from the others. 
** As far as we can see, the most essential external characters 
of the different orders of Arachnida must be taken from the 
Structure of (1) the mouth, (2) the antennz (first pair of limbs), 
.. (3) the other limbs, and oe the ides number of the abdominal 
segments. 
e s Pedipaipi. e o dell’ iden Malese, Ann. d. Mus. Civ. d. Stor. 
Nat. di Genova, vol. vi, PP- ne "de zd Ser. oe = 2 
Hn. A > PP- ae 
