HEMICHORDATA-PTEROBRANCHIA

Solitary or colonial,sessile and tubicolous animals living inside secreated chitinous tubes
Body short,compact,with stalk for attachement..
Proboscis shield-like.
Collar bearing ciliated arms.
Alimentary canal u-shaped
Anus dorsal lying near mouth
Ciliary feeding..
Gill-slits one pair or absent.
Sexes separate or united.
Gonads 1 or 1.
Asexual reproduction by budding in some.