ARTICULATA. 269 
carrying its eggs. The Squid (Lolzgo) and Cuttle - fish 
(Sepia) have ten arms, the additional pair being much 
longer than the others. Their eyes are movable, while 
those of the Argonaut and Poulpe are fixed. The Squid, 
so much used for bait by cod-fishermen, has an internal 
horny “pen,” and the Cuttle has a spongy - calcareous 
“pone.” The extinct Lelemnete had a similar structure. 
Subkingdom ARTICULATA. 
This is larger than all the other subkingdoms pnt to- 
gether, as it includes the jointed animals, such as Worms, 
Crabs, and Insects. These differ widely from the Mol- 
luscan type in having a symmetrical form, and in showing 
a repetition of similar parts, not only in the shelly exterior, 
but equally among the internal organs. 
The skeleton is outside, and consists of articulated seg- 
ments or rings. The limbs, when present, are likewise 
jointed and hollow. The jaws move from side to side. 
The nervous system consists mainly of a double chain of 
ganglia running along the ventral surface of the body 
under the alimentary canal. The brain is in the form of 
a ring encircling the gullet. The alimentary canal and 
the circulatory apparatus are nearly straight tubes lying 
lengthwise — the one throngh the centre, and the other 
along the back. There is a remarkable correspondence, 
especially in the lower forms, between the joints of the 
body and the ganglia of the nervous cord, the respiratory 
organs and the chambers of the dorsal heart. Each ring 
of a Worm has a complete circulatory, respiratory, and 
nervous apparatus.’ 
As we advance from the lowest forms (Worms), in 
which the body is elongated, the rings numerous, the 
skin soft, and the legs imperfect, we shall find the rings 
fewer, the skin firmer, and the legs more elaborately 
formed, as in the Centipede; till in the Bee, Spider, and 
