582 CLASS III. MYRIAPODA. 



him seminis opens with the oviduct. The male organs consist 

 of an unpaired testis placed dorsal to the gut and sometimes 

 partly or completely divided into two or more portions, and 

 of paired, somewhat complicated ducts, \vhich are united by 

 connecting canals and which open separately on the segment 

 of the second pair of fully developed legs through the copulatory 

 processes there found. 



Very little is known of the development. The just-hatched 

 young possess three pairs of legs and they attain the adult con- 

 dition by a series of moults. They can elongate and shorten 

 their bodies by contraction to a considerable extent. They 

 avoid light, living beneath objects (stones, wood, etc.) in damp 

 places. The more active forms prey on other microscopic 

 animals, and those which are more sluggish eat decomposing 

 animal and vegetable substances. 



The Pauropoda appear to represent a primitive group of Myria- 

 poda, with affinities to the Diplopoda by the incipient diplopody 

 shown in the relation of some of the terga to the leg -bearing seg- 

 ments, by the number of the jaw- appendages, by the condition 

 of the just-hatched young, by the unpaired gonad, and the posi- 

 tion of the genital opening. On the other hand in the dorsal 

 position of the testis they present a feature of similarity to 

 the Chilopoda. 



Fam. 1. Pauropidae. Head free and uncovered ; with rounded bodies, 

 long legs and agile movements. The trunk has 6 terga, feebly chitinized, 

 and the anal segment which is uncovered dorsally. The integument is 

 white and smooth. World-wide. Pauropus Lubbock (Fig. 346), more 

 than 21 species, P. Huxleyi Lubbock, British. Stylopauropus Cook, 

 ^S. pedunculatus Lubbock, British. 



Fam. 2. Brachypauropidae. Head free and uncovered. Terga of the 

 trunk consist of nine pairs of plates and an unpaired plate, all fairly 

 chitinized. Movement slow. Er achy paur opus Latzel, Austria and Italy. 



Fam. 3. Eurypauropidae. Head concealed beneath the first tergal 

 plate ; with depressed bodies, short legs and slow movement ; trunk 

 with 6 terga, firmly chitinized. The anal segment is hid beneath the 

 produced 6th tergum. Eurypauropus Ryder, N. Amer., Austria, Italy. 



Order DIPLOPODA * 



Progoneates with a head bearing two pairs of jaws (mandibles 

 and maxillae), a thorax consisting of four segments and usually 



* Latzel R., Die Myriopoden der Osterreichischungarischen Monarchic, 

 Zweite Halfte, Wien, 1884. Silvestri F., J. Diplopodi, Geneva, 1896. Id., 

 Classis Diplopoda, vol. 1, Portici, 1903. E. Metschnikoff, Embryologie 



