29 



Cryptoxymus viGiLA^fs. Hall, 1847. 



Plate ii, Fi9. 1 a-h. 



The cephalic shield is more than semiluna in form, 

 Avith its posterior angles produced into long sharp spines, 

 which, when j^erfect, extend to the pygidium ; their 

 extremities curve upwards. The glabella is not lobed ; 

 the front margin (limbus) is thickened, and marked 

 by two lines of nodes ; the eves are facetted, sub-coo- 

 ical and remarkably prominent. 



The surface of the head is marked by large tubercles ; 

 each node has a minute perforation or puncture at its 

 apex. The small hypostoma is ovate and attached to 

 the glabella. The thorax consists of 11 segments; the 

 pleurae are extended and three times the width of the 

 axis joints ; the axis of the thorax has on every second 

 joint a node or short spine. 



The pygidium is triangular and consists of 9 pleurae, 

 every alternate one being ornamented with a node : 

 the axis has about 18 rings, every third one being mark- 

 ed by a tubercle. 



Locality: Trenton Limestone ; Middleville, X. Y. 



Cryptonymtjs multisegmentatus, Portlock, 1843. 



Cephalic shield, with prolonged posterior angles : gla- 

 bella convex, clavate, being in front twice as wide as at 

 the base ; the surface is covered with large convex and 

 pointed nodes; the cheeks are separated from the glabella 

 by deep dorsal furrows, and are also covered with nodes. 

 The pygidium is triangular, with a conical axis, consist- 

 ing of many rings, about 32 or 33 ; but they are not 



