In this article we will discuss about:- 1. Origin of Dogfish 2. Systematic Position 3. Distribution 4. Habits and Habitat 5. Economic Importance. Origin of Dogfish: Pisces (Fishes) are aquatic, cold blooded vertebrates that breathe by means of gills and live in water. There are about 30,000 to 40,000 species of fishes differing widely from each other in shape, size, [...]
The locomotion of fishes has been explained by Breder (1926) and Gray (1933). By taking a series of photographs at definite intervals of time of a swimming fish against a background marked with a graduated scale. Gray has been able to record: (a) The motion of the body of the fish relative to the surrounding water, and (b) The movements [...]
In Dogfish (Scoliodon), the coelom is specious and is divided into two unequal cavities, the small anterior pericardial and the large posterior abdominal, separated from each other by a membranous partition, the septum transversum. Pericardial cavity is comparatively smaller in size and triangular in shape and lies beneath the pharynx enclosing the heart. It is enclosed between a tightly fitting [...]