The upcoming discussion will update you about the differences between Fishes and Tetrapoda. Difference # Fishes: 1. Fishes have paired appendages in the form of pectoral and pelvic fins. 2. Fishes respire by means of gills. 3. Except lung fishes they do not have internal nares. 4. Heart is 2 chambered except lung fishes where heart is 3 chambered. 5. [...]
The upcoming discussion will update you about the differences between Cartilaginous and Bony Fishes. Difference # Cartilaginous Fishes: 1. Cartilaginous fishes are mostly marine. 2. The mouth of cartilaginous fishes is ventral. 3. The external nares are ventral. 4. The scales of cartilaginous fishes are Placoid. 5. In cartilaginous fishes, operculum is absent except chimaera. 6. Caudal fins are heterocercal [...]
The below mentioned article provides biology notes on Phylum Hemichordata. (Gk. hemi- half, chordate- notochord) Due to some similarities with chordates, some workers considered Hemichordata as a subphylum under phylum chordata. But, on grounds of its general organization, recent scientists, like Vander Horst (1939), Dawyd off (1948), Marcus (1958) and Hyman (1959), have given it the status of a phylum [...]