Palaeozoic Aracknida of North America. 113 



Key to the Families of Phalangiotarbi. 



1. Third and 4th pair of coxae elongated, meeting in the median line. 

 First pair of legs slender and long 



Heterotarbidae 

 + All coxae triangular. All legs short and stout 2 



2. Coxae of first pair of legs contiguous throughout their entire length 



Architarbidae 

 + Coxae of first pair of legs contiguous only at their proximal end. 

 Between them are the coxae of the pedipalpi 



LIST OF DESCRIBED SPECIES OF PHALANGIOTARBI 

 Family Phalangiotarbidae. 

 Genus Phalangiotarhus Haase 1890. 

 I. P. suhovalis (H. Woodward) 



= Architarhus suhovalis H. Woodward, Geol. Mag. Vol. IX, 1872, 



p. 385, pi. IX, fig. I. 



P. suhovalis Haase, Zeits. d. g. Gesell., Vol. XLII, 1890, pp. 638, 



650, pi. XXX, fig. 3- 



= Architarhus suhovalis Fritsch, Pal. Arachn., 1904, p. 35, text 



fig- 39- 



P. suhovalis Pocock, Carb. Arachn., 1911, p. 46, text fig. .17. 

 From the Coal Measures of Lancashire, England. 



Genus Geratarhus Scudder 1890. 



1. G. acoei Scudder, Mem. Boston Soc. Nat. Hist., Vol. IV, 1890, 

 p. 448, pi. 40, fig. II. 



From the Pennsylvanic (Lower Allegheny) of Mazon Creek, 

 Illinois. 



2. G. minutus n. sp. 



From the Pennsylvanic (Lower Allegheny) of Mazon Creek, 

 Illinois. 



Discotarbus n. gen. 

 I. D. deplanatus n. sp. 



From the Pennsylvanic (Lower Allegheny) of Mazon Creek, 

 Illinois. 



Metatarhus n. gen. 

 I. M. triangularis n. sp. 



From the Pennsylvanic (Lower Allegheny) of Mazon Creek, 

 IlHnois. 

 Teans. Conn. Acad., Vol. XVIII. 8 June, 1913. 



