In this article we will discuss about the classification of chondrichthyes. Class 4. Chondrichthyes (Gr., chondros = cartilage; ichthys = fish): 1. Mostly marine and predaceous. 2. Body fusiform and spindle-shaped. 3. Fins both median and paired, all supported by fin-rays. Pelvic fins bear claspers in male. Tail heterocercal. 4. Skin covered with placoid scales or naked and bears mucous [...]
Crossopterygians or lobe-finned fish are now represented only by fossils. They were very dominant in Devonian times about 280 million years or more ago and became extinct by the end of Cretaceous. However, several living specimens of a specialised side branch, the Coelacanths, have been found in recent years since 1938 near Comoro Islands between Africa and Madagascar. Dr. J.L.B. [...]
The Superclass Pisces (L. Piscis = fish) are the truly jawed vertebrates. They have organs of respiration and locomotion related to a permanently aquatic life. The respiratory organs are the gills and the organs of locomotion are paired and impaired fins. All are poikilothermous. General Characters: 1. Aquatic, either freshwater or marine, herbivorous or carnivorous, cold blooded, oviparous or ovoviviparous [...]