XXI. A NEW AMERICAN CYBELE. 

 By J. E. Narrawav and Percy E. Raymond. 



American specimens of trilobiles of the genus Cybele are so ex- 

 tremely rare that a fairly complete indiYidual discovered by the senior 

 writer in the Black River formation near Ottawa, Canada, adds con- 

 siderably to our knowledge of American forms. Clarke has described 

 a nearly complete specimen of a species of this genus from the Mo- 

 hawkian of Minnesota (Paleontology of Minnesota, Volume 3, part 2, 

 page 762, 1897) ; Billings described the pygidium of another species 

 from the Quebec group of Newfoundland (Paleozoic Fossils of Can- 

 ada, Volume I, page 292, 1865); Ruedemann described a partial 

 pygidium from the Lower Trenton at Rysedorph Hill, near Albany, 

 New York (Bulletin of the New York State Museum, Number 49, page 

 66, 1902) ; and Raymond has described a species from the Chazy 

 formation at Valcour, New York. This last species was also founded 

 on specimens of the p3'gidium. 



The specimen now to be described is more perfectly preserved than 

 any so far found, except the one described by Clarke, from Minne- 

 sota, and fortunately preserves the glabella, a portion not previously 

 recognized in American forms of this genus.' This specimen, which 

 is a little less than five-eighths of an inch in length, shows the glabella 

 and the outline of one side of the cephalon, a large part of the free 

 and fixed cheek having been chipped off. The axial lobe is complete, 

 but about half of the left pleuron is gone, the fracture being at a low 

 angle with the axis, and not far from the axial lobe. The first six 

 segments of the thorax have also been somewhat damaged on the right 

 side. The pygidium is complete except for a small loss at the distal 

 end. All the important points, except the i)Osition of the eye and the 



1 Encriimrus iiiirns Billings, whicli was tlic (irst American species of Cybele de- 

 scribed (see locality cited above) was founded on detached glabell3e and pygidia. 

 The pygidium is undoubtedly that of a Cybele, but there is some doubt about the 

 cranidium. If it really is that of a Cybele, it is distinctly of the European type wath 

 three deeply incised glabellar furrows. Dr. Clarke has suggested that this cranidium 

 may belong to a species oi Amphion [PlioDwra). 



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