AND THE DEVELOPMENT OF THE MYRIAPODA. 
127 
longer than the others. The single ocellus has disappeared, and in its stead three 
distinct ocelli, arranged in a triangle, have been developed. The apex of the tri- 
angle is directed upwards. The ocelli are of two sizes, the largest, a single one, being 
at the posterior angle. The development of an increased number of ocelli in lulus 
at successive periods was discovered by M. Gervais, but the precise time of their ap- 
pearance has not before been indicated. The new segments of the body produced at 
the former change of the animal, from the eighth to the twelfth inclusive, are now of 
the same size as the original ones, and each has developed from it two additional pairs 
of legs, so that the whole number of legs is now thirty-four. The thirteenth, or if 
we may so term it, germinal segment of the last period, is less developed than the 
preceding ones, and is distinguished from them by the circumstance that it is smaller, 
possesses no legs, and has no lateral spot, which exists, as above stated, on each of the 
preceding segments, to the seventh, marking the existence of the foramina repugna- 
toria. The large patch on the seventh segment is now larger and darker than here- 
tofore, and the spots on the succeeding segments have been increased in size. The 
germinal space (13.g-), which existed in the preceding period, and was then seen to be 
forming segments, is now developed into six new apodal segments, from the fourteenth 
to the nineteenth inclusive, very much smaller and shorter than the rest ; and a ger- 
minal space ( h ) is again forming between the last of these and the penultimate seg- 
ment of the body, which, as above stated, undergoes no marked change. The whole 
body is thus composed of twenty-one segments, including the head. The first twelve 
of these are now perfectly developed, as well as the last two, the intermediate ones 
being only in their preparatory states. The antennae, parts of the mouth, legs, and 
anal segments, are still covered with minute hairs. At this period I gave my speci- 
mens for food some decayed leaves and rotten bark of the elm, as also some uncooked 
potatoe, on which they seemed to feed voraciously. They seemed to thrive most 
rapidly on the decaying bark, and grew daily, especially at the posterior extremity 
of the body. 
On the sixty-second day (fig. 22.) all the specimens had been lying quietly coiled up 
in a circle for nearly twenty- four hours, preparatory to again changing their skin. The 
segments, from the thirteenth to the eighteenth inclusive, which had been partially 
developed at the last change of skin, were now nearly completed, and exhibited the 
transverse impression of the perfect animal; and the future spots on the sides of 
these segments were now shining faintly through the old skin, which had become 
whitened and dried, exhibiting the peculiar appearance of the approaching change. 
Besides this, instead of the three ocelli developed at the last change, there were now 
five , which appeared through the tegument, still arranged in a triangle ; one of these 
was larger than the last, and distinctly formed of two parts, so that six ocelli were now 
about to appear. The number of legs still continued the same as at the last change. 
The nineteenth segment, which, at the period of transformation, was but a very soft 
fold of the tegument, with a slight division in the middle of it attached to the 
