120 
MR. NEWPORT ON THE ORGANS OF REPRODUCTION, 
period of throwing off this skin being fast approaching ; the double legs of the sixth 
and seventh segments, inclosed in their proper skin, were now more elongated, and 
very much enlarged, and the new segments were further developed, as well as the 
future germinal membrane (g). The external tegument was more extensively sepa- 
rated from the whole body, especially at the posterior part, and the head was re- 
tracted within it, and bent on the under part of the thorax. It was thus evident 
that this tegument was not of recent formation, that it simply inclosed the animal, as 
the whole had previously been inclosed in the amnion, as is proved by the circum- 
stance that it extended smoothly over the whole body, antennae and legs, and did 
not follow the inflexion or reduplication of the proper surface of the animal like the 
folds of the true skin beneath it, as in the original segments (14. 7 -), but passed di- 
rectly over them, and was simply protruded or extended by the growth of parts be- 
neath, as in the instance of the new legs ( b , c ). Up to this period the young lulus 
must still be regarded as in the embryo condition, although for a day or two after 
bursting the amnion, it possessed the power of locomotion, and evinced some deve- 
lopment of its peculiar instinct. At its next change of skin, when it enters what I 
regard as the fourth period of its development, and when it has acquired fourteen 
pairs of legs, it assumes for the first time a condition analogous to the larva state of 
true insects on bursting from the ovum ; the difference between the two being, that 
the analogue of this tegument of the embryo in insects is slipped off at the bursting 
of the amnion on leaving the shell, while that of the Myriapod is not thrown off until 
some days after it has entirely left the ovum. The correctness of this analogy is con- 
firmed by the fact, that the double legs, which may be regarded as the analogues of 
the abdominal legs of the Caterpillar, are not acquired until a late period in the deve- 
lopment of the embryo in insects, as I have seen in the embryo of the Caterpillar of 
one of the Saw-flies, Athalia centifolice, in which the first legs developed are the tho- 
racic, and at a little later period, while the larva is yet in the egg, the abdominal 
ones. The permanent state of lulus is thus strictly analogous to the transitory con- 
dition of the insect in the larva state, the relative development of the two being very 
similar. The Iulidse and other Myriapoda are thus connected, on the one hand, with 
insects in the larva state ; and, on the other, still more closely with the Annelides by 
the reproduction of segments of the body ; the repetition of the segments in lulus 
and other Myriapoda being one of the last occurrences in the higher forms of Arti- 
culata, in which distinct segments, or principal, and vital portions of the body are 
formed after leaving the ovum. This phenomenon almost entirely ceases in the higher 
families of Myriapoda, the Scolopendradse, in which the number of segments pro- 
duced is gradually diminished. I may here also remark, in proof of the persistence 
of the same principles in the development of the egg in true insects, that in Athalia 
centifolice I have found the animal in its shell inclosed in a distinct amnion, and that 
the funis enters the body of the embryo at a part precisely similar to that of the 
entrance of the funis in lulus, the posterior margin of the penultimate segment, the 
