PAUROPODA. 581 



one flagellum, and the ventral two flagella and the so-called 

 globulus. The flagella are ringed and the globulus, which may 

 be stalked or sessile, is probably a sense organ. There are 

 six well-marked tergal plates (except in the Brachypauropidae) : 

 of these each of the first five lies over two segments, while the 

 last is the tergum of the legless preanal segment. In addition 

 there is the anal segment with a tergum of its own, which 

 may be covered by the tergum of the preceding segment. The 

 appendages of the first segment are stump-like and small. The 

 other trunk appendages (nine pairs) are legs which are set wide 

 apart on the sterna and terminate in claws ; the first and last 

 pairs of these are five- jointed, the remainder being usually six- 

 jointed. There are five pairs of long tactile hairs which project 

 from the sides of the body beneath the second to the sixth tergal 

 plates. The adult males have copulatory organs at the base of 

 the legs of the third pair (counting the reduced legs as the first). 



The alimentary canal consists of a short foregut (oesophagus), 

 a long dilated midgut, usually receiving at its hind end two 

 malpighian tubes (absent in Pauropus * etc.), and of a short 

 conical rectum with a chitinous lining. The anus is at the^end 

 of the anal segment. There are three pairs of salivary glands 

 opening into the inner part of the mouth. The brain is large 

 and fills up the greater part of the head, and the ventral cord 

 possesses nine ganglia. There is no distinct body-cavity but 

 the space between the organs is occupied by a fat-body com- 

 posed of large cells. Heart and blood-vessels are absent. 



Special respiratory organs appear to be almost completely 

 absent. The only traces of them are two very fine, structure- 

 less tubes opening on the head at the base of the mandibles and 

 not extending back beyond the first body segment. These are 

 interpreted by P. Schmidt as tracheae. They are without nuclei 

 in their walls. The general integument, which is remarkable for 

 its thinness, must serve as a respiratory surface. 



The female genital organs consist of an unpaired ovary, ovi- 

 duct, and receptaculum seminis. The ovary is a longish tube 

 lying ventral to the gut and extending from the fourth to the 

 eighth segment. The single oviduct opens behind the second 

 pair of fully developed legs in the middle line. The receptacu- 



* Absent elsewhere in Tracheates in Japyx, Peripatus, Cottembola and 

 some Arachnids. 



