32 



characters ; tlie first to six pleurae are nearly cylindri- 

 cal, smooth, and terminating with rounded extremities, 

 which incline towards the front.* 



The sixth pleurae is about twice the thickness of the 

 others ; it gently slopes posteriorly until it reaches the 

 fulcrum point, where it is suddenly bent at an angle of 

 90° to the rear, and runs parallel with the axis, termi- 

 nating in a long pointed spine ; the other segments 

 conform with this one, and gradually diminish in size 

 as they approach the posterior extremity of the animal. 

 The pygidium consists of four pleurae : the axis is 

 pointed, and marked with 16 notches, which do not ex- 

 tend across it ; the first four notches only have pleurae. 

 The pleurae as they approach their ends run almost 

 parallel with a line drawn through the centre of the 

 axis ; the last pair are united at their extremities. 

 Length one and one-half inch. 



Locality : Wesenburg, Wanuamois, Russia. 



Cryptonymus (Cybele) atkactopyge. 3IcCoy, 1851. 



The pygidium is obtusely triangular ; the axis, which 

 becomes narrower, consists of about 16 rings, only the 

 first four extending across it, and have pleurae; the 

 others are notched on the sides : its surface is marked 

 with two lateral rows of convex tubercles (7 on each 

 side) ; the last pair are in the middle of the axis. 



*NoTE — Angelin figures a copy with an attached process to the second seg- 

 ment ; and future observation may develop the fact that the five anterior 

 pleurse have distinct fulrcum points at their rounded extremities, with a sep- 

 arate articulated attarhmsnt. Should this be so, all the pleura would con- 

 form to the sixth. 



