M. Fabre on the Development of the Myriapoda. 1G3 



segmeiits, both in the male and female. With the progress of 

 development the animal gradually acquires a greater number of 

 segments and feet. The author has followed this progress up 

 to the eighth stage, when the animal has acquired a length of 

 20 mill., and possesses twenty segments, not including the head ; 

 at this period we find thirty pairs of feet in the male and thirty- 

 one in the female; and it is only then that the copulative organs 

 make their appearance. From his observations he derives the 

 following laws: — 1. Each new segment appears between the 

 anal and penultimate segments. 2. All the apodal segments in 

 one stage become pedigerous in the next. 



Some authors have asserted that the lull are produced in an 

 apodal state, others that they are born hexapod. M. Fabre has 

 been able to study the eggs of his /. aterrimus. Escaping from 

 these he saw a singular body entirely destitute of any appendi- 

 cular organs, and not presenting the least resemblance in form 

 to the animal from which it was produced. This, which the 

 author calls the pupoid body {corps pupo'ide), is reniform, deeply 

 excavated beneath, convex above, large and rounded at one of 

 its extremities, a little narrowed and conical at the other; its 

 surface is smooth, shining, and of a pure white; it exhibits no 

 movements, even when pricked with a needle. Five days after 

 its exclusion distinct traces of segmentation are seen in this 

 body, and in the thickness of the inflated end the head begins 

 to be perceptible, folded down upon the abdomen. Seven or 

 eight days afterwards, it splits, and the young animal makes its 

 appearance, with the characters attributed by De Geer and Ger- 

 vais to the lulus at the moment of its birth. 



This young IuIuls^ when just excluded, is li miil. in length; 

 it is completely white, formed of seven segments, not including 

 the head, and furnished with three pairs of feet, v/hich corre- 

 spond with the first three pairs of the adult ; the antennse are 

 composed of four joints. In proportion as the development 

 takes place, the eyes, which at first were only one on each side, 

 increase rapidly in number, and the older parts of the body 

 acquire a deeper colour. The lulus aterrimus is not completely 

 adult and fit for reproduction before the end of two years ; and 

 the life of these animals must apparently be pretty long. M. 

 Fabre has kept adults in captivity for two years. 



In the Chilopoda, the ovigenous and spermagenous organs, 

 although complicated, present no remarkable anatomical arrange- 

 ment. This is not the case with their products, which, in Sco- 

 lopendra, Cryptops and Geophilus, are enclosed in capsules which 

 M. Fabre thinks he may compare with the spermatophora of the 

 Cephalopoda and of some Crustacea. In Scolopendra and Cry- 

 ptops the spermatophora are formed in the most inflated portion 



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