PERIPATUS

PERIPATUS

·        
Peripatus 
belongs phylum onychophora.

·        
First reported by Guilding

·        
Exhibits discontinuous distribution.

·        
Regarded as the Connection ling between
phylum Arthropoda and Annelida.

·     
External characters:

·        
Body cylindrical

·        
Smooth Velvet like body surface with
papillae

·        
External segmentation absent

·        
Head bears three pairs of appendages

·        
A pair of simple eyes are present

·        
Body wall is dermo-muscular

·        
Body cavity 
is haemocoel

·        
Heart is tubular. Blood vascular system
without blood vessels.

·        
Excretion is by nephridia.

·        
Glands are present in the body wall.

·        
Exhibits Viviparity .

Affinities:

·        
Affinities with annelids:

·  Presence
of thin transparent cuticle on the body

·  Segmental
arrangement  of nephridia

·  Absence
of distinct head

·  Hallow
appendages resemble the parapodia.

·       Affinities
with arthropods:

·   Appendages modified into jaws

·   Body cavity haemocoel

·   Respiration through
trachea

·   Presence of a pair of salivary glands

·   Blood without colour.

·      Special
Characters:

·    Segments are in uniform nature

·    Single jaw in the mouth

·    Absence of external
segmentation

·    Ladder like nervous system