318 Fredertck (■ha/pinan: 



spines, on our limestone samples. Tliis is mentioned merely as 

 ji point worth consideration. 



Horizon. — Upper Cambrian. Agnostus Zone. Dolodrook 

 River. 



Ptychopai'ia minima, sp. nov. 

 (PI. LVIII., Figs. 1 and (?) 6 ; PI. LIX., Fig. 22). 



Xote. — The subjoined description is founded princijaally on 

 a cephalon without the free cheeks : but a pygidium occurring 

 in the same limestone is also tentatively referred to the ^iresent 

 species. 



Description. — Glabella subcylindriual, comparatively long, 

 tapering very slightly anteriorly ; upper surface finely pustulate, 

 with three distinct lateral furrows, the two posterior broad, 

 shallow, and with a strong backward curve ; neck-furrow deeply 

 impressed, the neck-ring showing traces of a slight ridge bear- 

 ing three small blunt spines directed posteriorly. Anterior 

 border of glabella nearly semcircular, but somewhat truncated 

 in front, broad and depressed. Palpebral lobes large, pro- 

 minent, elliptical ; eyes narrow, sublunate and strongly curved. 



Pygi'dium (provisionally referred to this species), compara- 

 tively large, with about six well-defined segments. Axial lobe 

 prominent, rounded, rapidly tapering to a point at the posterior 

 border: narrower than in 1'. tliieh-i ; lateral lobes moderately 

 wide, slightly rounded, and depressed in relation to the axial 

 lobes ; sutures neatly and clearly marked. Margin broader 

 than in P. thieJei, and with conspicuous striae parallel with 

 the border. 



Dimensions. — Length of glabella from base of neck-ring to 

 anterior border, 6.5 imn. ; greatest width of glabella, 3.25 mm. 

 Length of palpebral lobes about 2 mm. ; greatest width of 

 neck-ring, 1 mm. 



Pygidium, provisionally referred to this form, length, 7.5 

 mm.; greatest width, 11 mm.: greatest width of axial lobe, 

 2.2 mm. ; width of border, 1.25 mm. 



Observations. — The cranidium upon which the above specific 

 description is based is of the same general type as that of the 



