Raymond and Barton. — American Species of Ceraurus. 



PLATE 1. 



Fig. 1. Ceraurus pleurexanthemus Green. A restored figure, based princi- 

 pally on the specimen, (No. 4 Coll. M. C. Z.), Plate 2, fig. 1. 

 The posterior part of the pygidium is restored from another 

 specimen (No. 2 Coll. M. C. Z.). The top of the left eye is in- 

 complete, as in the specimen, while the right eye is restored. The 

 specimens on which this figure is based are from the Trenton at 

 Trenton Falls, N. Y., Coll. M. C. Z. The figure is one half larger 

 than natural size. 



Fig. 2. Ceraurus dentatus Raymond and Barton. A typical pygidium from 

 the Trenton at Watertown, N. Y. The specimen is No. 7 Coll. 

 M. C. Z. and the figure is one half larger than natural size. 



Fig. 3, 4. Ceraurus bispinosus Raymond and Barton. Figure 4 represents 

 the incomplete cranidium which is the holotype of this species, 

 and fig. 3 was made from a free cheek which is believed to belong 

 to the same species. Both specimens are in the private collection 

 of Mr. J. E. Narraway of Ottawa, Ontario, and are from the Black 

 River limestone at Tetreauville, Que. The figures are one half 

 larger than natural size. 



Fig. 5. Ceraurus numitor (Billings) . An incomplete cranidium, from which 

 the neck-spine is broken. From the English Head formation 

 (Richmondian) at English Head, Anticosti. The specimen is 

 No. 8 Coll. M. C. Z., and the figure is one half larger than natural 

 size. 



Fig. 6. Ceraurus milleranus Miller and Gurley. A small enrolled specimen 

 from the Lorraine at Cincinnati, Ohio. A part of the pygidium 

 projects from beneath the glabella. The specimen is No. 9 Coll. 

 M. C. Z., and is two and one half times natural size. 



Fig. 7. The same species. A nearly complete specimen (No. 10 Coll. M. 

 C. Z.) from the Lorraine at Cincinnati, Ohio. The figure is one 

 tenth less than natural size. 



Fig. 8. The same species. A photograph of the holotype, which was col- 

 lected from the Lorraine at Cincinnati, Ohio, and is now in the 

 Walker Museum at the University of Chicago. The figure is one 

 sixth less than natural size. 



