Fill in the blanks `:`
(i) Four characters of Chordates are the presence of `"…......."` dorsal hollow nervous system, `"…................."` and muscular tail.
(ii) Urochordates are marine, sessile, `"….................."` feeding invertebrate chordates. Common example is `".................."`
(iii) Agnatha are the most primitive Craniates. They are commonly called `"................"` vertebrates.
(iv) Electric ray belongs to class `"..................."` while sea horse belongs to class`".................."`
(v) A lizard - like reptile `".............."` of New Zealand is a living fossil.
(vi) Snakes and lizards belong to class `"..............."` while frogs and toads are included in class`"................."`
(viii) `".................."` are also defined as feathered dipeds. These have a lone `"................."` gland on the tail.

Explanation

(i) notochord, pharyngeal slits (ii) filter, Herdmania ( the sea squirt ) (iii) Jawless (iv) Chondrichthyes, Osteichthyes (v) Sphenodon ( the tuatara) (vi) Reptilia, Amphibia (vii) Birds , uropygial ( preen or oil ) .