JS^oles onMyriapoda. 3 



tlie middle line to form a single prestcrnite. In addition to 

 the plates ali'cadv nientioued, there is a series of varvinff 

 niiiuljcr and anangement, whieh i'ornis the eupleuriiun. 

 For [)urposes of eoniparison, Briilemann has numbered the 

 rows of these plates in the following way .- — 



The row which includes the stigiuata-bearing ))late is 

 designated by the number 1 ; the episternal row, the row 

 nearest to the sternite, is 2 ; 3 is the row next below 1 ; -l is 

 next to 2 and consequently just above the legs, 5 is the row 

 between 3 and 4. Then, since each row is theoretically 

 composed of three selerites, each plate is indicated by an 

 index-letter : the anterior selerite is designated by the index 

 a, the middle one by /3, and the posterior one by 7 (fig. 2). 



Fig. 2. 



Thtilthyhin^ microcephalus. Integumentary selerites displayed. 



st 53., sternite of the lifty-fifth trunlc-segment; pst., presternite ; tf/, ter- 

 pite ; pff/, pretergite ; the other lettering is explained in the text. 

 This animal has a complete eupleurium, consistini>- of five rows witli 

 every element represented. J. W. Smith & S. G. B.-B. phot. -del. 

 [After Brolemann, (3) p. 313, fig. 1.] 



Briilemann (3) points out that in all Geophilomorphs 

 row 1 is constant, except that in some cases the selerites are 

 independent, while in others (Oryinse) the presclerite a may 

 be fused with the stigmatiferous selerite /3. Row 2 is 

 equally constant ; only a single case is known (^Treinatonja) 

 where the ])resclerite is lacking. Only rarely are they 

 complete, more often one or other of the three rows is 

 incomplete and is only represented by two selerites or even 

 only by a single one, or again one of the rows may even lie 

 completely wanting. 



The sternite is often pierced by a number of minute 

 circular perforations, wlfich are collectively known as the 



1* 



