ART. 21 OKDOVICIAN TEILOBITES — ULEICH 5 



ranged in quincunx, varying greatly in size and number, in some 

 as few as 15 transverse rows, in others as many as 50 rows between 

 Iia^^e and top of eye. 



Thorax with broad axis, well defined dorsal furrows, and narrow 

 ])leural areas; axial part of segments each with a single or two 

 closely approximated short, backwardly directed nodes or spines; 

 pleural part of segments grooved, outer extremity more or less 

 acuminate. Number of segments unknown. 



Pygidium small, subtriangular to subpentagonal ; axis strongly 

 convex, sharply defined, wide in front, tapers rapidly and extends 

 nearly to the posterior extremity; pleural lobes narrow, practically 

 unsegmented ; axis with two, rarely three, rings, all with one or two 

 median spines, the second and third usually with a small post-lateral 

 node on each side. General appearance of pygidium varies consider- 

 ably in different species, the difference being in details rather than 

 essential respects. The posterior edge may be simply rounded or 

 drawn out into a flat median spine. 



Genotype. — Telephus fractus Barrande. 



Stratigraphic range. — Ordovician and earliest Silurian. 



Origin and center of dispersal. — Middle Atlantic realm. 



Geographic distribution as in the following tabulation of species : 



GEOGRAPHIC DISTRIBUTION AND STRATIGRAPHIC POSITION OF SPECIES OF TELEPHUS 



European species 



Telephus fractus Barrande, Bohemia, D 4 and D 5. * 



Telephus granulatus Angelin, Norway and Sweden, upper half 

 Ogygiocaris shale. 



Telephus hicuspis Angelin, Norway and Sweden, lower half 

 Ogygiocaris shale. 



Telephus haddingl, new species, Sweden, lower half Ogygiocaris 

 shale. 



Telephus wegelini Angelin, Sweden, Trinucleus shale. 



Telephus mohergi Hadding, Sweden, base of Ogygiocaris shale. 



Telephus Unnarssom, new species, Delarne, Sweden, Leptaena 

 limestone. • 



Telephus hihernicus Reed, Ireland, Tourmakeady Beds. 



Telephus rffedi, new species, Girvan District, Scotland, White- 

 house group. 



Telephus F salteri Reed, Girvan District, Balclatchie group. 



Americmi species 



Telephus aniericanus Billings, Newfoundland. Div. N and P. 

 Telephus mysticensis, new species. Mystic, Quebec, probably 

 Blount age. 



