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 [...]
The blood vascular system includes the heart, blood vessels (arteries and veins) and blood. Heart and Pericardium: The heart of Dogfish (Scoliodon) lies mid-ventrally beneath the pharynx in the head region. It is a simple dorso-ventrally bent S-shaped muscular tube. It lies in the pericardial cavity, bounded by a two-layered membranous pericartium. It is a median triangular cavity lying between [...]