538 bulletin: museum of comparative zoology. 



belonged was large, apparently two or three times the size of the one 

 to which the type belonged. 



Formation and locality. — Ccraurus bispinosus is known only 

 from the Black River limestone, Tetreauville, P. Q. 



Ceraurus milleranus Miller and Gurley. 

 Plate 1, fig. 6-8; Plate 2, fig. 6. 



t Calyment bucklandi Anthony, Amer. journ. sci., 1839, 36, p. 106, 

 % 1, 2. 



Ceraurus milleranus Miller and Gurley, Bull. Illinois state mus. nat. 

 hist., 1893, p. 80, pi. 8, fig. 10. 



Ceraurus does not seem to be particularly plentiful in the vicinity 

 of Cincinnati, and the vertical range would appear to be very limited. 

 According to Nickles, (Journ. Cine. soc. nat. hist., 1902, 20, no. 2), 

 Ceraurus milleranus is found only in the Corryville division of the 

 Lorraine. 



In the Dyer collection in the M. C. Z. there are a number of speci- 

 mens of Ceraurus collected at Cincinnati, none of them absolutely 

 complete, but several of them nearly entire, and well preserved. 

 These specimens differ from specimens of Ceraurus pleurexanthemus 

 at Trenton Falls in having shorter and less flaring spines at the genal 

 angles, and in having the eyes less elevated, and further back. 



Two names have been applied to the Cerauri at Cincinnati. The 

 Calymene bucklandi of Anthony is evidently, from the figure, a Cerau- 

 rus, but the revival of his name is objectionable, because the type 

 is not now accessible, the figure and description are poor, and the 

 original specimen is not complete enough to show the important char- 

 acters, should it ever be found. The other name, Ceraurus milleranus, 

 is open to many of the same objections, but fortunately we have, 

 through the kindness of Professor Weller, been able to study the type, 

 which is No. 6,062 in the collection at the Walker Museum of the 

 University of Chicago. This specimen agrees with the other speci- 

 mens from Cincinnati in the length of the genal spines and the position 

 of the eyes, but the pygidium is peculiar, in having the tips of the 

 great spines very close together. We have before us twenty good 

 pygidia from Cincinnati, and none of them show this feature, although 

 there is some approximation toward it in one or two specimens. We 

 believe that this feature, which Miller and Gurley considered the most 



