CHAPTER XVII 
TRACHEATA 
Ciass I, PROTOTRACHEATA 
OnycHoPHoRA (PERIPATIDEA), Peripatus 
CHARACTERISTICS.— Animals with soft caterpillar-like bodies, 
with a pair of antennae, a pair of jaws, a pair of oral 
papillae, and numerous pairs of walking legs, each bearing 
claws. Respiration by means of tracheae, the stigmata of 
which are numerous and scattered.  Nephridia present. 
The Prototracheata include a single genus, Peripatus, which 
is morphologically one of the most interesting animals known ; 
its developement, made known to us chiefly by the researches 
of Sedewick, is also of the highest morphologicai import, 
and our recently-acquired knowledge of it has solved many 
problems of Arthropod structure. Its distribution is also 
interesting; it has been found in New Zealand, Australia, the 
Cape of Good Hope, South America, the West Indies, and 
possibly in Sumatra. 
Peripatus capensis is a very beautiful-looking animal, of a 
velvety green colour dorsally, shading off into an orange-brown 
on the under surface. The female is larger than the male, and 
when adult may measure 65 mm., the male being about three- 
quarters as long. The skin is thrown into numerous ridges, 
which are beset with a number of papillae, each bearing a spine. 
Appendages of Peripatus capensis. 
1. Antennae. 
2. Jaws in buccal cavity, armed with two cutting blades. 
3. Oral papillae, with orifice of slime glands. 
0. Seventeen pairs of clawed walking-feet. 
1. Anal papillae. 
