36() 



Annals ok the Carnk(;ie Museum. 



Billings' species. This is, however, the only species of Ceraurus in 

 our collections with a subrectangular glabella and isolated posterior 

 glabellar lobes. (See figure 6. ) Glabellae of this sort are quite com- 

 mon in the trilobite layers at Sloop Bay, where they accompany the 

 following species, but can always be easily distinguished from it. 



5 



7 



Volume One of the 



Figs. 4, 5- Sphccvexochus parvus Billings. 

 Fig. 6. Ceraurtts poiupilius Billings. 

 Figs. 7> 8. Platyntetopus minganensis Billings. 

 Fig. 9. Remipleurides canadensis Billings. 

 Figures 4 to 9 are reproductions of Billing's original figures in 

 Paleozoic Fossils of Canada. 



Description. 



Glabella subrectangular, broadly rounded in front; moderately 

 convex. Three pairs of glabellar furrows ; the first two pairs nearly 

 parallel to the neck furrow, while the last pair turn abruptly back, 

 joining the neck furrow. Neck segment wide, separated from the 

 glabella by a deep furrow. Fixed cheeks wide, triangular and bearing 

 the genal spine, which is very long and slightly bowed. Eye small, 

 situated opposite the third glabellar lobe and about 2 mm. from it. 

 Free cheeks small. Whole surface papillose, the pustules being small 

 and thickly scattered over the glabella and cheeks, but rather sparingly 

 on the margins and spines, where there are large, smooth intervals. 



Measurements — A cephalon : length 6 mm.; width 19 mm.; 

 length of genal spine, 13 mm.; width of glabella, 5 mm. This is 

 about the average size. 



This species is very closely allied to Ceraurus polydorus Billings, 

 from Table Head, Portland Creek, Newfoundland, which may account 

 for the fact that the latter species has been listed from Valcour Island, 

 by Brainerd and Seely. 



Locality. — Trilobite layers. Sloop Bay, Valcour Island. A single 

 specimen was found on the north end of Sloop Island. It occurs also 

 in the Mingan Islands, Canada. 



