T o Download Lecture in pdf form go to end of the page Vertebrates (Fishes) Phylogenetic Relationships: Fishes: Sub-Phylum Craniates. Skull Surrounded the brain Having sense organs such as OLPHACTORY ORGANS Eyes Inner ears Classification of Fishes      Fishes are divided into 2 infra phylums (1)      Infra phylum h…

Urochordates: They are marines known as sea squirts They are solitary or colonial Fixed or free-swimming Numerous gill slits are present The body is covered by a cuticle called a tunic. only in Larval Stages notochord is present. Dorsal tubular nerve cords are present in the larval form while degenerate in the form of the small …

go to the end of this page to dowload pdf Classification of chordates: They have 45,000 species      Generally, classified into 3 Sub-Phylums. (1) Sub-Phylum Urochordates (2) Sub-Phylum Cephalochordates (3) Sub-Phylum Craniata 1. Sub-Phylum Urochordates: Their notochord, nerve cord, and post-anal tail are present only in free-sw…