A NEW AND ANNECTANT TYPE OF CHILOPOD. 441 



Class Cliilopoda. 



Opisthogoueate tracheate Arthropods descended from a 

 primitive type iu which the body consisted of a lai'ge number 

 of metameres similar in size and form, each with a bi'oad 

 tergal and sternal plate, connected by a pleural membrane, 

 a pair of stigmata, and a pair of short hexarthrous, mon- 

 onychous appeudages. At an early phylogenetic stage the 

 stigmata disappeared from the last three somites in con- 

 nection with the special functions these somites \vere set 

 apart to fulfil, the last or anal losing its appendages and being 

 degraded to the condition of a carrier of the anal orifice ; 

 the penultimate or genital being, like the anal, reduced in 

 size as a safeguard against damage, but retaining its 

 appendages in a dwarfed form as manipulators of the ova 

 or spermatophores ; and the antepenultimate or last leg- 

 bearing somite having its appendages enlarged and directed 

 backwards to protect the genital somite, and, in later 

 stages, to become modified as tactile, offensive, or secondary 

 sexual organs. Anteriorly two pairs of appendages, retain- 

 ing a primitive biramous structure, were set apart as 

 gnathites ; and a single pair, lying in front of the latter, 

 consisting of not fewer than fourteen homonomous segments, 

 and widely separated at the base, as antennee. The dorsal 

 area of the three somites represented by the appendages 

 just mentioned was covered by a single plate, the cephalite 

 or head shield, which was furnished laterally with eyes, and 

 was curved downwards in front over the mouth to form a 

 labruni or upper lip. For seizing and holding prey, the 

 six-jointed appendages of the two metameres behind the 

 head were turned forwards towards the mouth, their basal 

 segments becoming enlarged and encroaching upon the 

 sternal area, each appendage at the same time under- 

 going a partial axial rotation, so as to fold in a horizontal 

 rather than a vertical plane. The first pair of these appen- 

 dages i-etained its primitive pediform structure, while in 



