It seems probable that it is identical with one of the open sacs in which each shell-plate of a Chiton is formed, and the series of plate-like imbrications which are placed behind the single shell-sac on the dorsum of the curious slug, Plectrophorus, suggest the possibility of the formation of a series of shellsacs on the back of that animal similar to those which we find in Chiton.
The eggs may be laid separately invested by a chitinous envelope, or as in Ischnochiton magdalenensis they may form strings containing nearly 200,000 eggs, or the ova may be retained in the pallial groove and undergo development there, as in Chiton polii and Hemiarthrum setulosum.
This is the condition of the nervous system found in Chiton and the other Amphineura, but may not be in all respects the ancestral condition.
Dorsal view of Chiton Wosnessenksii, Midd., showing the eight shells.
In works of art Hygieia is represented, together with Asclepius, as a maiden of benevolent appearance, wearing the chiton and giving food or drink to a serpent out of a dish.
In the common species of Chiton and many others of the family Chitonidae the megalaesthetes are developed into definite eyes, the most complicated of which have retina, pigment within the eye, cornea and crystalline lens (intra-pigmental eyes) (fig.
View from the pedal surface of a species of Chiton from the Indian Ocean.
The long chiton was regularly used by musicians (e.g.
The long linen chiton, which had been worn by men as well as women, was now only retained by the male sex on religious and festival occasions; a short chiton was, however, worn at work or in active exercise (Greek Art, fig.