30 



clearly defined. Small tubercles can be seen on the axis 

 of the pygidium, along its centre. The number of 

 pleurae is generally nine, very seldom ten. (Nieszk.) 



The original description of this species is as follows : 

 "Axial segments very narrow and numerous, 28 being 

 enumerated as far as the last side segments, and still 

 continuing, though very minute, to the very apex. A 

 small lozenge shaped caudal plate. Side segments 12 

 on each side, exclusive of the false segment. They are 

 rounded, and slighty bent or raised at their extremities ; 

 no punctures or marks of any kind." Salter's descrip- 

 tion of the pygidium gives 30 axis rings and 12 pleurae. 



"We would suggest that the species described by Niesz- 

 kowski, be cited as a variety under the name of Orypt, 

 Nieszkoivskii. 



Lower Silurian : Tyrone, Montgomeryshire, Ireland ; 

 Neuenhof, near Hapsal, Russia, etc. 



Cryptonymus (Cybele) kex. Nieszhoivski, 1857. 



The cephalic shield is semilunar. The glabella is 

 clavate in form, prominently convex in the middle, and 

 has on each of its slopes three deep oval notches; its 

 surface is marked by four pair of smooth tubercles, 

 placed in two lines and converging posteriorly towards 

 each other. The marginal border (limbus) has in front 

 of the glabella five short equi-distant spines, giving to 

 the glabella a crown; this border is wide and thick, 

 and its surface is covered proportionally with large 

 round tubercles, placed in irregular lines. The course 

 of the facial suture is the same as it is in the other spe- 

 cies of this group, and has a row of small nodes on each 



