150 PALAEONTOLOGY OF NEW YORK. 



Observations. Cyphaspis craspedota is not an uncommon species in the basal 

 limestones of the Hamilton group in the township of Canandaigua, where a 

 few entire individuals and parts of several hundred others have been found. 

 Its occurrence in other localities of this formation has not been noticed. The 

 species is closely allied to Cyphaspis Burmeisteri, Barrande (Sys. Sil., vol. i, 

 ]>. 484, pi. xviii, figs. 61-71), from the etages D and E. This similarity is 

 apparent in the general form and proportions, the position of the eyes, length 

 of the genal spines and character of the surface ornamentation. Moreover the 

 sixth thoracic segment in C. Burmeisteri bears a strong spine, as in our species, 

 but the occipital ring and fourth segment in the former species, are without 

 spines. Barrande has also shown that the number of thoracic segments for 

 mature individuals of his species is fourteen; in immature examples varying 

 from seven to thirteen. All the entire individuals of C. craspedota show but 

 twelve segments. The pygidium of the Bohemian species is also larger and 

 more strongly segmented. C. craspedota probably finds a congener in the 

 C. hydrocephala, Maurer, of the German middle Devonian (Fauna der Kalke 

 von Waldgirmes bei Giessen, pi. xi, figs. 20-22, not C. hydrocephala, A. Roemer, 

 L845; Barrande, 1852; Kay ser, 1878). 



Distribution. Hamilton group. In the shales and limestones directly over- 

 lying the Marcellus shales: Near Centerfield, township of Canandaigua, Ontario 

 county. 



Cyphaspis l^evis. 



PLATE XXI, FIG. 29. 

 PhUUpsia Imoli, Hall. Illustrations of Devonian Fossils, pi. xxi, fig. 29. 1876. 



salon minute, outline semi-elliptical ; surface convex; border conspicuous, 

 elevated and rounded, produced at the genal angles into moderately long, 

 slightly incurving spines; marginal sulcus deep; frontal area evenly convex. 

 Facial sutures normal, crossing the frontal area somewhat abruptly. 

 Glabella sub-ovoid, convex ; basal lobes sub-pyriform, conspicuous; antero- 

 lateral depression faint. Occipital ring not retained. 



