Palaeozoic Arachnida of North America. 33 



three genera, Isohuthus, Eobnthus and Palaeohuthus. They may be 

 distinguished as follows : 



1. Abdominal sternites with straight posterior edges. Sternum 

 triagonal Palaeohuthus n. gen. (see below). 



Genotype P. distinctus n. sp., from Mazon Creek. 

 + abdominal sternites with posterior edges curved, so that the 

 sternites appear bilobed 2 



2. Sternum rhomboidal Genus Isohuthus Fritsch 1904 



Genotype and only species /. kralupensis Th. and L., Kongl. 

 Svensk. Akad., Vol. 21, No. 9, 1884, p. 17. Fritsch, Pal. 

 Arachn., 1904, p. 70, fig. 88; pi. 10, figs, i — 11. 



Found in the Coal Measure of Kralup, Bohemia. 



+ sternum oval Genus Eohuthus Fritsch 1904 



Genotype E. rakovnicensis Fritsch. 

 Described species : 



1. E. rakovnicensis Fritsch (ad partem), Pal. Arachn., 1904, 

 p. 74, figs. 90, 92 ; pi. 8, figs, i, 2. Pocock, Carb. Arachn., 

 1911. p. 13. 



Found in the Coal Measures (Noegerathienschiefer) of 

 Rakonitz, Bohemia. 



2. E. holti Pocock, Carb. Arachn., 1911, p. 14, fig. i ; pi. II, fig. 2. 



From the Coal Measures of England. 



Family Cyclophthalmidae. 

 Late Palaeozoic scorpions with normal arrangement of coxae, mid- 

 dle eyes not close to the anterior edge of the cephalothorax, hand 

 comparatively wide with short fingers and sternum "pear "-shaped. 

 This family contains three genera from Europe and one from North 

 America. 



Genus Cyclophthalmus Corda 1835. 

 Genotype C. senior Corda, 



1. C. senior Corda, Verh. Ges. vaterl. Mus. Bohmen, 1835, P- S^. 

 Fritsch, Pal. Arachn., 1904, p. 66, figs. 84—86; pi. 7, figs. 1—4; 

 pi. 8. figs. 3-5. 



From the " Steinkohlensandstein " of Bohemia. 



2. C. euglyptus (Peach) 



= Eoscorpius euglyptus Peach, Trans. Roy. Soc. Edinb., Vol. XXX 



1883, p. 402, pi. XXII. 

 C. euglyptus Pocock, Carb. Arachn., 1911, p. 19, fig. 4. 

 From the Lower Carboniferous (Cementstone) of Scotland. 



Genus Palaeomachus Pocock 1911. 

 Genotype and only species P. anglicus (Woodward). 

 Trans. Conn Acad., Vol. XVIII. 3 June, 1913. 



