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 [...]
The endoskeleton is composed entirely of cartilage hardened at places by calcifications. The true bones are entirely absent. The endoskeleton can be divided into: (i) Axial skeleton comprising the vertebral column, the skull and (ii) Appendicular skeleton including the pectoral and pelvic girdles and the skeletal elements of fins. Axial Skeleton: Vertebral Column: The vertebral column comprises a chain of [...]
In this article we will discuss about the digestive system of dogfish (scoliodon) with the help of suitable diagrams. Alimentary Canal: The alimentary canal of Dogfish (Scoliodon) comprises the mouth, buccal cavity, pharynx, oesophagus, stomach, intestine and rectum opening in the cloaca through anus. a. Mouth: It is a ventral crescentic opening guarded by upper and lower lips which are [...]