SEGMENTATION OF THE HEAD OF DIPLOPODA. 607 



On the Segmentation of the Head of Diplopoda. 



By 



I?Ini'g^arct Robinson, 



University College, London. 



With Plate 37 and 6 Text-fljjures. 



Introduction. 



Through the kindness of Professor Minchin and Mr. 

 Pocock I have been able to examine embryos and larvee of a 

 South African species of Archispirostreptus from Port 

 Elizabeth. The adult specimens were obtained by Mr. 

 Pocock for the Zoological Society, and the eggs were laid in 

 the insect house at the Society's gardens. 



The work Avas undertaken with a view to finding out, from 

 embryological evidence, the number of segments and 

 appendages concerned in the formation of the Diplopod 

 gnathochilarium. Unfortunately none of the larvee from 

 the two batches of eggs that were laid lived long enough to 

 allow the development of the gnathochilarium to be observed. 

 The examination of some of the embryos has, however, led 

 to one or two interesting results, and incidentally to the 

 solution of the gnathochilarium problem itself. 



Many thanks are due to Mr. Pocock, who spent much of 

 his valuable time in preserving the earlier stages daily. 



Historical Sketch. 



In an account of the developmental stages of several 

 Chilognatha, Metschnikoff (1874) states that in them the 



VOL. 51, part 4, — NEW SERIES, 45 



