315 



(Fig-. 258.) 



genal 



Fig. 258. Cryphceus 

 booihi. var. calliteles. Py- 

 gidium (after Hall and 

 Clarke). 



common, and it occurs in the shales below the Trilobite 

 beds in Avery's Creek. 



Cryphceus boothi, var. calliteles. Green. 

 (Pal. N. Y., Vol. VII., p. 45, Pis. XVI., XVI. A.) 



Distinguishing Characters. — Long;, flat, tapering 

 spines, their acute extremity reaching to 

 the eighth thoracic segment, their 

 flattened end grooved by the occipital 

 furrow; wide occipital ring, with cen- 

 tral spiniform node ; thorax ambulations 

 with spiniform nodes, increasing in size 

 backwards ; distant, narrow, lanceolate 

 pygidial spines ; faintly grannlose surface, with glabella and 

 pygidial lobes usually quite smooth. ' 



Found in the Encrinal limestone, at Section 5 (rare) ; also 

 in the Trilobite beds of Section 8, etc., associated with the 

 preceding. 



Genus PROETUS. Steininger. 



[Ety. : Mythological name.] 

 (1831: Mem. Soc. Geol. de France.) 



Cephalon semi-circular, with thickened margins. Glabella 

 very convex, parabolic, rounded anteriorly, with few lateral 

 furrows. Eyes prominent, smooth, 

 close to the glabella. Thoracic seg- 

 ments ten, pleurae with oblique fur- 

 row. Pygidium trilobed, semi-circu- 

 lar ; axis short and convex. 



Proetus macrocephalus. Hall. 

 (Fig. 259.) (Pal. N. Y., Vol. VII., p. 

 116, Pis. XXL, XXIII.) 



Distinguishing Characters. — S u b - 

 semi-circular or lunate cephalon ; thin 

 acute genal spines ; sub-conate, pustu- 

 lose glabella, with sides broadly taper- 

 ing to the anterior extremity, its 

 width three-fourths the length ; single 



Fig 



Proetus macro- 

 cephalus. Outline of a speci- 

 men (after Hall and Clarke). 



