TRiLoiirrKs of iin-: Chazv Limkstone. 367 



Ceraurus hudsoni sp. nov. (Plate 14, figure 15.) 

 Associated with the species just described is another common si)e- 

 cies, much resembling Ceraurus pleiirexaiitlieDius oi \\^t Trenton. To 

 this abundant and fine species I wish to give the specific name, hudsoni, 

 in honor of Professor (reorge H. Hudson, of the Plattsburgh Normal 

 School. Professor Hudson is an earnest student of the C'hazy fauna, 

 and to him 1 am under many obligations. 



Description. 



Cephalon. — Glabella broad, prominent, gently convex, expanding 

 considerably toward the front. (Glabellar furrows, three pairs, parallel 

 to the neck furrow, the posterior pair turning back to join the neck 

 furrow. Neck segment wide, convex, highest posteriorly. Fixed 

 cheeks large, convex, extended at the genal angles into long spines 

 which appear to be somewhat more divergent than in Ceraurus pom- 

 pilius. Free cheek small. Eyes small, situated opposite the second 

 glabellar lobe and some distance from the glabella. Glabella and 

 cheeks covered with strong pustules of various sizes, many quite large. 

 The genal spines and borders are ornamented with small, distant 

 papillae. 



Thorax and pygidium unknown. 



Afeasureinenfs. — A cei)halon : length 8 mm.; width 19 mm.; 

 width of glabella in front, 7.5 mm., behind, 5 mm. Another: length 

 II mm.; width 24 mm.; width of glabella in front, 10 mm., behind, 

 7.5 mm. A third: length 9.5 mm.; width 27 mm. 



This species is closely related, on one side, to Ceraurus poiiipilius 

 and, on the other, to Ceraurus pleurexanthemus. From C. poinpilius 

 it differs in having the glabella expanded toward the front and in the 

 much larger and more prominent pustules on the surface. From C. 

 pleurexanthemus it differs in having the cheeks smaller and more con- 

 vex, and in having the eye further forward. 



Locality. — Trilobite layers. Sloop Bay, Yalcour Island. 



Subgenus Pseudosph.urexochus Schmidt. 

 Pseudosphaerexochus vulcanus. (Plate 14, figure 16.) 



Cheirurus Vulcanus Billings, 1S65, Paleozoic Fossils Canada, volume I, page 284, 



figures 271, a, b, c. 

 Cheirurus pioUpicus Billings, 1S65, Paleozoic Fossils Canada, volume i, page 285 



figure 273 ; page 325, figures 311, 312. 



