PERIPATUS ONYCHOPHORA Dr N SRINIVAS LECTURER IN ZOOLOGY

PERIPATUS ONYCHOPHORA Dr. N. SRINIVAS LECTURER IN ZOOLOGY PR GOVT. COLLEGE (AUTONOMOU) KAKINADA

PERIPATUS Peripatus is a terrestrial animal mostly confined to humid habitats.

PERIPATUS ØFirst reported by Guilding ØConfined to onychophora by Moseley the presence of trachea Ø

PERIPATUS

External Morphology ØBody is caterpillar-like soft, elongated, bilaterally symmetrical Ø 1. 4 cm to 15. 00 cm in length

External Morphology External segmentation is indistinct and marked only by the presence of paired appendages

External Morphology Ø Body is divisible into head and trunk. Ø Head bears a pair of antennae, a pair of oral papillae, a pair of mandibles. Ø Trunk bears 14 -41 appendages

External Morphology Ø Appendages are hallow, consists of two parts 1. Leg and foot Ø Leg is wide hallow structure, ends with spiniferous pad. Ø Spiniferous pad continues as clawed foot.

Characters Ø A nephridiopore lies at the base of each leg helps in excretion. Ø Body wall is dermo-muscular Ø Body cavity is haemocoel Ø Glands are present in the body wall.

Characters ØHeart is tubular with ostia. ØBlood vascular system without blood vessels. ØRespiration is by the trachea

Characters Ø Only the muscles of mandibles are striated and the rest are smooth muscles. Ø Nervous system and sense organs are similar to annelids and arthropods Ø Exhibits Viviparity.

Affinities Ø Affinities with annelids: Ø Presence of thin transparent cuticle on the body Ø Segmental arrangement of nephridia Ø Absence of distinct head Ø Hallow appendages resemble the parapodia.

Affinities Ø Affinities with arthropods: Ø Appendages modified into jaws Ø Body cavity haemocoel Ø Respiration through trachea Ø Presence of a pair of salivary glands Ø Blood without colour.

Affinities Ø All segments are of similar in nature Ø Velvet like body wall Ø Mouth with a jaw Ø Absence of external segmentation