IV 

 A NEW CERAURUS FROM THE CHAZY 



BY PERCY E. RAYMOND 



Several years ago the writer collected the hypostoma of a large 

 Ceraurus from the lower part of the" Upper Chazy (zone with 

 Glaphurus pustulatus) at Cooperviile, New York. The 

 hypostoma was much too large to belong to Ceraurus hud- 

 son i and so was not described in my first paper on the Chazy 

 trilobites, but a figure found a place in the second paper, in 1910. 

 Recently Doctor Ruedemann was good enough to call my attention 

 to a very large Ceraurus which he had collected at the same horizon 

 in the Chazy at Little Monty bay, Chazy, N. Y. Through the 

 kindness of Doctor Ruedemann I am permitted to describe this 

 particularly interesting species. 



The specimens in the New York State Museum are five in 

 number, two incomplete cranidia, two free cheeks, one retaining 

 the visual surface of the eye, and an incomplete pygidium. 



> 

 Ceraurus ruedemanni sp. nov. 



Plate 30, figures 9-12 



Undetermined hypostoma, Raymond. Annals Carnegie Museum, 

 v. 7, no. 1, pi. 19, fig. 22. 1910. 



Specific diagnosis. A large Ceraurus with somewhat depressed 

 glabella ornamented with small pustules, the axial portion of the 

 glabella isolated from the side lobes by the longitudinal furrows. 

 Pygidium with strongly developed " great " spines and one pair of 

 long spines between the " great " spines, these inner spines being 

 developments of the second segment. 



The glabella is roughly rectangular in outline, rather more flat- 

 tened and more finely pustulose than most species of Ceraurus. The 

 outline of the front is not rounded, but shows three straight edges. 

 There is a narrow, slightly pustulose anterior rim separated from 

 the glabella by a narrow, smooth furrow. The width of the glabella 

 expands toward the front, but the axial" lobe, which is distinctly 

 isolated from the glabellar lobes by a pair of longitudinal furrows, 

 expands very slightly. The frontal lobe is short and narrowed at 

 the sides. In the middle of the front there is a shallow rounded 



