130 MR. NEWPORT ON THE ORGANS OF REPRODUCTION. 



ferred, from this fact, that this is the number of segments produced at each change 

 in all the Chilognatha, or that the new segments are produced in a corresponding 

 part of the body in the other divisions of this class, the Chilopoda. In these two 

 orders the parts in which the new segments appear differ greatly, and most distinctly 

 mark these two divisions of the Myriapoda. In the Chilognatha the segments are 

 always produced as above stated, but in the Chilopoda, the proper Scolopendradse, 

 according to Gervais% the new parts are developed between each of the original 

 segments. These are remarkable differences in the modes of growth of the two 

 orders of this aberrant and most singular class. Although the new segments make 

 their appearance at the same part of the body in all the Chilognatha, they differ in 

 number in different animals of this group, and from the few observations I have yet 

 made, I am inclined to believe that this difference is characteristic of different genera. 

 Thus in lulus terrestris it is sextuple through the earlier periods of life, but in a 

 well-defined genus, Blaniulus, nearly related to lulus, the number of segments at each 

 reproduction appears to be quadruple, while in the young of another genus, which 

 I believe to be Polydesmus, closely connected with the above, the number of seg- 

 ments appears to be only twofold at each change. But in each of these instances 

 the number of new segments is similar throughout the earlier changes of the animal. 

 The development of legs takes place subsequently to that of new segments, which, 

 when first produced, are always apodal, the legs being developed to the new segments 

 at the next change of tegument. Bujt as regards the number of legs produced, this is 

 less regular than that of the segments. Thus in the hexapodous condition of the 

 animal, legs are being produced to only two of the original apodal segments beneath 

 the common tegument, while six new segments are in progress beyond them. When 

 the skin is thrown off the legs are elongated, and the segments become more deve- 

 loped. In the mean time new legs are being formed beneath the tegument for those 

 new segments, while other new segments are being produced beyond the last of these 

 organs of locomotion. In like manner the eyes make their appearance as one of the 

 last commenced changes, while theantennse are the parts that earliest attain their full 

 development. Such are the conclusions at which I have arrived in these investiga- 

 tions, which I propose to continue at a future period. 



* Loc. cit. 



ill I 



^ 1 



