536 bulletin: museum of comparative zoology. 



mus in having the eyes further forward and the cheeks more convex, 

 but the figures in the Palaeontology of New York with which compari- 

 son was made were those which we now refer to C. dentatus. Ceraurus 

 hudsoni has the flaring spines of C. pleurexanthemus, and the eyes agree 

 with that species in being nearer to the glabella than to the posterior 

 margin of the cephalon. The glabella seems to be broader and less 

 convex than in C. pleurexanthemus, and the rate of expansion is a 

 little greater (about 1 mm. in 4). There is, however, little difference 

 between the two species, so far as can be seen in the incomplete 

 specimens so far found. 



Formation and Locality. — This species has been found only in 

 the Middle Chazy on Valcour Island, New York. 



Ceraurus granulosus, sp. nov. 



Ceraurus pompilius Raymond (non Billings), Annals Carnegie 

 mus., 1904, 3, p. 365-6 (not fig. 6), pi. 14, fig. 14; 7th rept. Vermont 

 state geol., 1911, p. 240, pi. 36, fig. 14. 



This species was originally identified by Raymond with Billings's 

 species, Cheirurus pompilius. Billings's figure shows the glabella of 

 Ch. pompilius to be smooth and his description states that the cheeks 

 are punctured. The specimens from Sloop Bay, identified by Ray- 

 mond as Ch. pompilius, have the whole surface papillose, the pustules 

 being small and thickly scattered over the glabella and cheeks, but 

 rather sparingly on the margins and spines. It therefore seems best 

 to refer these specimens from Sloop Island to a new species. 



From Cheirurus pompilius Billings, Ceraurus granulosus is distin- 

 guished by the granulose condition of the cephalon and from the other 

 species of Ceraurus, by the parallel-sided glabella, and by the faint 

 granulation. 



Formation and Locality. — Trilobite Layers, Chazy, Sloop Bay, 

 Valcour Island, N. Y. 



Ceraurus bispinosus, sp. nov. 



Plate 1, fig. 3, 4. 



This species is known only from a fragmentary specimen of a cepha- 

 lon showing the glabella and one fixed cheek. The fragment shows 

 C. bispinosus to have been a ceraurid of medium to large size. The 



