CHAPTER XVII 
ARACHNIDA EMBOLOBRANCHIATA (CONTINUED) — PODOGONA— 
PHALANGIDEA = OPILIONES— HABITS—STRUCTURE—CLASSIFI- 
CATION 
Order VII. Podogona (Ricinulei). 
Tracheate Arachnids with two-jointed chelate chelicerae and 
prehensile pedipalpt. The tarsus of the third leg of the male bears 
a copulatory organ. 
In 1838 Guérin-Méneville’ described an Arachnid from 
West Africa which he named Cryptostemma westermannii. At 
rare intervals occasional specimens of allied forms have been 
taken in the same region until 
six species of Cryptostemma have 
been — established. In South 
America, also, two unique ex- 
amples of very similar creatures 
are the only known representa- 
tives of the two species of the 
allied genus Cryptocellus. All 
the examples hitherto found are 
of fair size (between + inch and 
+ inch in length), and bear some 
general, though superficial, resem- 
blance to the Trogulidae, which 
has led to their being placed 
among the Phalangidea by almost er os ee ) . 
all the Arachnologists who have 
noticed them. Their claim to this systematic position, however, 
is extremely doubtful, and Hansen and Sorensen, who have had 
the opportunity of studying the group much more minutely 
1 Revue Zoologique par la Société Cuviertenne, p. 10. 
439 
