Question

In dissecting a worm, why would the worm be arranged dorsal side up and why would you cut off-center along the dorsal side?

Answer 1

The ventral side of worm is flatter than the other side. The dorsal side is rounded up. For dissection a worm should be placed on it ventral side, that is with the dorsal side up.

Worms are annelids which means their body are composed of multiple ring like sections or segments.

The dissection is to be started from about an inch posterior to the clitellum. If cut too deep it may damage the internal organs. The center is cut-off along the dorsal side because of bilateral symmetry ie; if you cut down the centre , can find that the left and right part of the body are identical or symmetrical. The dorsal side is prefferred to cut because most of the nerves are present in ventral surface. Deep incision can damage the nerves and intrnal organs.