Cephalopods have developed sense organs

Cephalopods have developed sense organs, especially eye structure. The structure of the Nautilus eye is relatively simple, forming a spherical capsule with rod-shaped body layer, pigment layer and retinal cell layer, without crystals. The eye structure of squid and other subclass animals is similar to that of vertebrates.

The base of the eye is supported by cartilage to form an eye socket. The eye includes conea, lens, ciliary muscle traction on both sides of the lens, and iris diaphragm on both sides of the front edge to adjust the size of the pupil, Control the amount of light entering. The focal length of the crystal is fixed. The pupil is often crack-shaped and often remains level. The lens is filled with colloidal liquid. The bottom of the eyeball is the retina. The retina is a layer of rod-shaped cells containing pigments. It is a photoreceptive cell outside the retina.

For the optic nerve. The optic nerve is connected to the huge optic ganglion. The skin outside the eyeball can also form eyelids, and the eyelids are very developed in the eight arms, and its contraction can completely cover the eyeballs. From the structural point of view, this kind of eye can undoubtedly be able to image, especially the ability to distinguish between horizontal and vertical projection of objects should be very strong. However, the vision range of cephalopod eyes is still very limited compared with that of vertebrate eyes.