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 [...]
In this article we will discuss about the process of reproduction in dogfish with the help of suitable diagrams. Copulation: During copulation one or both the claspers of the male are inserted into the cloaca of the female and are fixed in position by the erection of terminal pieces. The spermatic fluid is forced through the grooves of the claspers [...]