Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: May 4, 2025
But the plan or fundamental scheme of these eyes is correct and capable of indefinitely greater development than the organs of touch or smell, perhaps greater even than the otolith vesicle. And the reflex influence of the eye on the brain was the greatest advantage of all.
In each chamber is a membranous sac containing an otolith, and the auditory nerves pass from the cerebral ganglia into the cartilaginous chambers to reach the auditory sacs. Here, then, we have a wonderful coincidence indeed; two highly complex auditory organs, marvellously similar in structure, but which must nevertheless have been developed in entire and complete independence one of the other!
In a very few turbellaria we find otolith vesicles. These are little sacks in the skin, lined with neuro-epithelial cells and having in the middle a little concretion of carbonate of lime hung on rather a stiffer hair, like a clapper in a bell. Such organs serve in higher animals as organs of hearing, for the sensory hairs are set in vibration by the sound-waves.
There are tentacles and otolith vesicles as very delicate organs of feeling, or possibly of hearing also. But the annelids were probably the first animals to develop an eye capable of forming an image of external objects. The importance of this organ in the pursuit of food or the escape from enemies can scarcely be over-estimated.
Word Of The Day
Others Looking