The tail vertebrae of the dogfish have this typical arrangement, the trunk vertebrae have the haemal arches modified.
The haemal arches (basiventralia) differ much in the trunk and tail portions of the vertebral column.
Haemal arches similar to the neural arches are often found as in Urodela.
The neural and haemal arches and spines are cartilaginous and interbasalia (intercalary pieces) are present.
The ventral or haemal arches meet one another ventrally and send out processes to protect the ventral vessels.
