THE JULUS TERRESTRIS. 
423 
especially along the ventral surface. It was less able to move 
than before, the period of throwing off the skin being fast ap- 
proaching ; the double legs of the sixth and seventh segments, 
enclosed in their proper skin, were now more elongated, and very 
much enlarged ; and the new segments were further developed, 
and the germinal membrane also. Up to this period the young 
Julus is still essentially in an embryonic condition, and it does 
not acquire the peculiarities of a true larva until the approaching 
change of skin. This took place by the twenty-sixth day, and 
the Myriapod was found to have seven pairs of legs and fifteen 
segments to its body. The antennae had become elongated by 
at least one-third of their original length, and exhibited at least 
six distinct joints. The eye still consisted of a single ocellus, but 
this was now surrounded by a darker-coloured portion of the tegu- 
ment. The new legs were equal in size and length to the original 
ones, and were evidently more feeble. The transverse markings on 
the seven anterior segments were very distinct, and the large brown 
patch on the seventh ring was darker in colour (Figs. 7 and 8). 
The whole body was considerably elongated, and this was pro- 
duced chiefly by the extension of the new segments formed by the 
germinal membrane. The penultimate and the anal segments, of 
course, had undergone no change, and they never possess legs. 
By the forty-fifth day more segments were added, and the 
Julies began to be torpid, and lay coiled up in a spiral form. 
The tegument of the body began to assume a whitish, crustaceous 
appearance, and the animals secreted themselves beneath any dry 
covering, but avoided parts which were too wet. The principal 
changes in their general appearance were in the eyes, each ocellus 
being much more distinct, and in the germinal space, which was de- 
veloped to its greatest extent ; the six new segments were defined. 
The change of skin is effected in the following manner : — 
The young Julus , when about to cast its integument, bends its 
body in a semicircular form, with its head inflected against the 
under surface of the second segment. In this condition it remains 
for several hours, with its legs widely separated and the dorsal 
(back) surface of the segments extended. The head is then 
bent more forcibly on the chest, and a longitudinal fissure takes 
place on the top of the head, and extends outwards behind 
