These are also known as the cartilaginous fishes. They have an endoskeleton of cartilage and are cold blooded. The placoid scales form the exoskeleton and are dermal in origin. They do not have a gill cover so the gills are uncovered. Their jaws are well ...

There are a lot of differences between a Pisces and tetrapoda. The pisces include the fishes which have paired appendages known as pectoral and pelvic fins. They respire by gills and have dermal scales which form the exoskeleton. The tetrapoda include the amphibian, mammalian, reptilian ...

There are a lot of differences between a lamprey and hagfish. The lamprey occurs in the fresh water as well as act a marine. It acts both as a parasite and non parasite. It may grow up to 1 meter, while the hagfish is mainly ...

These are also known as the jaw vertebrates. In this case the notochord is present in the embryo stage. It disappears in the adult stage and is replaced by the vertebral column. They have a pair of nostrils and a multiple semi circular canals in ...

The agnatha are also known as the jaw less vertebrates. They do not posses jaw and are primitive type of organisms. They have notochord throughout their life. They are cold blooded and have no appendages and exoskeleton. The small neural arches which extend from the ...

The phylum chordata is divided into different sub phyla. These are known as the urochordata, cephalochordate and vertebrata. They all have different features and they are described below. The urochordata is also known as the tail notochord. They are also known as tunicata, as their body ...

There are certain characteristic features of the phylum chordata. They have a notochord which is like a solid and stiff rod. It is flexible and is present on the mid dorsal side. It lies between the alimentary canal and central nervous system. It is present ...