suBPHYLUM II MYEIAPODA 791 



head fiised with the thorax ; abdomen segmented, apparently broadly joined to the 

 cephalothorax ; between the tergites and steniites one or two rows of pleural 

 sclerites ; anus witli an operculiim wliicli represents the tergite of the eleventh 

 Segment ; chelicerae not known ; pedipalpi short, pediform ; legs seven-jointed with 

 niovable coxae apparently articulated to a sternum. Änthracomartus Kartsch (Fig. 

 1525); Brachypyge and Eophrynus Wood ward (Fig. 1526) ; Maiocercus and Trigono- 

 tarhus Pocock ; and Kreischeria Geinitz are Carboniferous genera. 



The Order Haptopoda is also confined to the Paleozoic. Head fused with the 

 thorax ; abdomen segmented, broadly joined to the cephalothorax ; pedipalpi short, 

 pediform ; pleura soft, withont sclerites ; tarsus of the first pair of legs seven-jointed. 

 Plesiosiro Pocock, from the Carboniferous of England, is the solitary known genus. 



The Order Phalangiotarbi, like the two preceding Orders, is Paleozoic. Head 

 fused with the thorax ; al)domen broadly joined to the cephalothorax, segmented, 

 with soft pleura devoid of sclerites ; 

 several anterior tergites very short, wdth a 

 thickened posterior edge ; anus with an 

 operculum, representing the tergite of the 

 twelfth Segment ; chelicerae not observed ; 

 pedipalpi short, pediform. Phalangiotarbus 

 Haase ; Geratarbus Scudder ; and Archi- 

 tarhus{= Geraphrynus) Scudder (Fig. 1527); 

 Opiliotarhus Pocock; Discotarhus ^Vetruiik., 

 etc., are Carboniferous. 



The Order Phalangida or Opiliones 

 (Harvest -Spiders) has many fossil repre- 

 sentatives, most of which are preserved in 



Oligocene amber. Head fused with the -^ • ^^ 



thorax ; abdomen broadly joined with the Fig. 152Y. 



cephalothorax, segmented, the anal oper- ArcUtarhus rotundatus Scudder (=Geraphrynus 

 pnlnm ro-nrpcjpnf in» fliP tprcrifp nf tTiP tpnfli carbonaHus Scudder). Goal Measures ; Mazon Creek, 

 culum representing tue tergite ol tue tentn ^^^^^^^^^ un^er surface. i/i (after Petrunkevitch). 



Segment. Chelicerae three-jointed, chelate; 



pedipalpi pediform ; coxae of the first, often also of the second and tliird pairs of legs 

 with maxillary lobes ; one pair of tracheae. Nemastomoides Thevenin ; Dinopilio 

 Fritscli ; and Protopilio Petrunk,, all from the Carboniferous, are referred to this 

 Order. The first-named of these, however {Nemastomoides claveris Thevenin), may 

 possibly belong to the Anthracomarti. 



The Order Acarina, Äcari, or Rhynchostomi (Mites, Ticks, etc.) comprises degenerate 

 Arachnids in which the abdomen is usually not segmented and is either broadly 

 joined to the cephalothorax or completely fused with it. Coxae of pedipalpi fused 

 together ; coxae of legs widely separate, without maxillary lobes. Numerous fossil 

 representatives are known from Oligocene amber and Tertiary freshwater deposits, 

 the majority of species being referable to Recent genera. Through the Opiliones this 

 Order appears to be connected with the Spiders. 



SuBPHYLUM B. Myriapoda Latreille/ 



Tracheate Arthropods with distinctly separat ed head bearing a single pair of 

 antennae, and a soma composed of numerous {at least twelve) fairly similar segments 



^ Literature : Fritsch, A., Fauna der Gaskohle, vol. iv. Prague, 1899-1901. — Orinnell, F., 

 Quateniary Myriapods and Insects of California. Univ. of Cal. Publ., Dept. Geol., 1908, vol. v. — 

 Koch, 0. L., Die Myriapodeu. Regensburg, 1847. — Koch, G. L., and Berendt, J. C, Die im 

 Bernstein bettndliclien Crustaceen, Myriapoden, Arachniden und Apteren der Vorwelt. Berlin, 



