The Collaborative International Dictionary of English v.0.48:

Peripatopsis \Pe`ri*pa*top"sis\, Peripatus \Pe*rip"a*tus\prop.
   n. [NL., fr. Gr. peri`patos a walking about.] (Zool.)
   The type genus of Peripatopsidae, consisting of
   onychophorans (lowly organized invertebrates related
   evolutionarily to the arthropods, also called "walking worms"
   AND "velvet worms") found chiefly in Asiatic and African
   tropical regions, in South Africa, Australia, New Zealand,
   and tropical America.

   Syn: genus Peripatopsis.
        [1913 Webster + WordNet 1.5]

              The average resident of the Northern Hemisphere is
              probably not familiar with the Onychophora; they
              are restricted to forest regions of South America,
              Africa, the Caribbean, and Oceania. Shy creatures,
              able to hide in incredibly tight crevices, these
              "velvet worms" (about ninety living species known)
              are rarely seen even in their natural habitat. Yet
              onychophorans are of great interest to biologists,
              because they seem to be related to arthropods, and
              give us an idea of what the ancestors of the
              arthropods may have been like. Although they are
              rare as fossils, a number that have been found
              from the Cambrian period. These fossils show that
              abundant marine relatives of the Onychophora
              flourished in the seas 520 million years ago.
                                                  --From:
                                                  http://www.ucmp.berkeley.edu/onychoph/onychophora.html
        [PJC]

   Note: In the 1913 Webster Peripatus was identified with the
         now disused order Malacopoda (within the phylum
         arthropoda); however, Malacopoda is now assigned to a
         group contained within the phylum Onycophora. The name
         Peripatus has also been used (possibly erroneously) to
         designate a specific species, as indicated in the
         following quotation found on the internet.
         [PJC]

               The onychophora, peripatus, is a unique creature,
               found in New Zealand. There is no other like
               peripatus. It is probably a creature from the
               dawn of time, as it seems to have a fossil
               representative of the most early invertebrates:
               Aysheaia, as may be found in some deposits of
               Burgess Shale.
               Aside from a lovely name, Peripatus doesn't look
               much like an earth creature. It is also
               frequently colored blue. It has a mixture of
               attributes similar to both annelida and
               arthopoda. I have also found interesting the
               arguments taxonomists have had for years over the
               creature; it's taxonomy has been fussed and
               fought over, and changed several times. Mostly,
               there just isn't anything like it.
               Its pre-historic relative (which looks just like
               it), lived at a time when mother nature was just
               begining to make complex, multi-cellular
               creatures, and most of them (with the exception
               of the jellyfish) looked like pure experiments in
               physical design. No decendants remain of them,
               except Peripatus. They were all bizzare in the
               extreme, like something from a sci-fi nightmare.
               And they are all gone.
               Except Peripatus. Peripatus still remains. It is
               totally bizzare, and totally unique. --Jonathon
                                                  R. Oglesbee
         [PJC]

WordNet (r) 3.0 (2006):

Peripatopsis
    n 1: type genus of Peripatopsidae; onychophorans of chiefly
         Asiatic and African tropical regions [syn: Peripatopsis,
         genus Peripatopsis]