CLASS CEPHALOPODA. if 
Their brain, which is contained in a cartilaginous cavity of 
the head, gives off a cord on each side, which produces a large 
ganglion in each orbit, whence are derived innumerable optic 
filaments. The eye consists of several membranes, and is 
covered by the skin which becomes diaphanous in that parti- 
cular spot, sometimes forming folds, which supply the want of 
eye-lids. The ear is merely a slight cavity on each side near 
the brain, without semi-circular canals, or an external meatus, 
where a membranous sac is suspended, which contains a 
little stone. 
The skin of these animals, of the octopi particularly, 
changes colour in places, by spots, with a rapidity which 
greatly surpasses that of the chameleon. 
The sexes are separated. The ovary of the female is in the 
bottom of the sac; two oviducts take up the ova and pass 
them out through large glands which envelope ‘them in a 
viscid matter, and collect them into clusters. The testis of 
the male, placed like the ovary, communicates with a vas 
deferens, which terminates in a fleshy penis, situated on the 
left of the anus. A bladder and prostate terminate there like- 
wise. ‘There is reason to believe that fecundation is effected 
by sprinkling, asis the case with most fishes. In the spawn- 
ing season, the bladder contains a multitude of little filiform 
bodies, which, by means of a peculiar mechanism, are rup- 
tured the moment they reach the water, where they move 
about with great rapidity, and diffuse a humour with which 
they are filled. 
These animals are voracious and cruel; possessed both of 
agility and numerous modes of seizing their prey, they destroy 
immense quantities of fish and crustacea. Their flesh is eaten; 
their ink is employed in painting, and the Indian or China 
ink is supposed to be made from it. 
The cephalopoda comprise but a single order, which is 
divided into genera, according to the nature of the shell. 
