THE yULUS TERRESTRIS. 421 



measured about a line in length, and exhibited the nine original 

 segments, the first seven being strongly marked. In the space 

 we have called the antepenultimate, six new segments were now 

 developed ; these were still very small, the length of the whole 

 being equal to that of one of the others. At that time they 

 did not form independent divisions of the body, but were covered 

 by the common skin or tegument. The last segment of the body 

 and the penultimate are permanent, and are not divided off into 

 the segments which make their appearance from time to time, 

 and these are really new growths. 



The skin covering the whole body is thrown off, and then the 

 Jiibis appears with the six^ new segments mentioned above, and 

 ready for food. It will be observed that additional legs have 

 begun to grow. Hitherto the Jtdus has had three pairs, but four 

 additional pairs are in course of formation, and they exist at this 

 period as nipple-shaped prominences on the under surface of the 

 sixth and seventh segments, four on each, and covered by the 

 common skin or tegument which is beginning to fall off. The 

 three pairs of legs that now exist are attached as follows : — One 

 pair to the prothorax or second segment, one to the third, and 

 one to the fifth segment. The general appearance of the animal 

 has now become less delicate, the head has acquired a darker 

 colour, and a faint broad patch is making its appearance at the 

 anterior part of the seventh segment. This patch (Figs. 5, 6, 7) 

 is permanent through all the earlier changes, and is of the greate.st 

 utility in determining how new segments are produced. Such was 

 the condition of the young Jitlus an hour after leaving the mem- 

 branes. It soon began to exhibit its animal powers, to show the 

 instincts peculiar to its species, and to be sensibly affected by 

 external causes. In less than six hours the little creature was 

 in motion. At first the antennae were the organs employed, 

 and they were moved slowly to and fro, and appeared to gain 

 power by use. In a short time the limbs began to be extended, 

 and the animal slowly raised itself upon them for the first time. 

 Its first efforts at locomotion were exceedingly feeble, but it 

 gradually gained strength. At the end of twelve hours the Julus 

 crawled about slowly, but moved its antennae briskly. On ex- 

 posing the insect to a strong light, a marked effect was produced 



