62 SYSTEMATIC ARRANGEMENT 



The cheek-shields are therefore broad, thickened at the entire exterior margin, pro- 

 minent, produced beyond the anterior part of the central shield, and furnished with very 

 small eyes above at their highest point, towards the posterior part beside the posterior 

 margin of the outermost lobe of the glabella. 



The body-rings (eight in number*) are small, but strongly arched, and the lateral lobes 

 are situated on one plane ; each has an elevated transverse ridge, and a long terminal 

 spine directed obliquely and posteriorly. 



The caudal shield has a short two-jointed axis, only one elevated lateral rib, but large, 

 strong, marginal spines at the exterior circumference. The surface of the body is regularly 

 covered with tubercles and knobs. 



Locdihj. — In the upper Silurian and Devonian strata of the Eifel, Silesia, and England. 



1. 0. ovata : Corpore ovate, dilatato, tmdique fimbriatim spinoso ; lobis trunci bispinosis, scuto 

 caudae duodecies spinoso. Long. % inch. Table II, Fig. 11. 



Emmr. Diss. .53, adj. tab. Fig. 3 ; Batfics tubercuhttiis, Klöden, Verst. der Mark 

 Brcnidoihiirr/, 112, Plate I, Fig. 16-23. 



This remarkable species occurs in a yellowish, liver-brown limestone, found as a boulder 

 in Silesia by M. Bocksch ; the only known specimen was presented to the collection at Berlin 

 by M. Dechen, and I am indebted to the latter gentleman for description and figure. 



The circumference is a broad ellipse, the transverse diameter of which is more than 

 two thirds of the longitudinal diameter. The length of the cephalic shield occupies 

 rather more than one sixth of it ; the glabella is smooth in the centre, granulated at the 

 sides ; the two succeeding smaller tubercles beside it are minutely granulated, the third 

 external one has three more considerable eminences before the region of the eye, and many 

 smaller ones ; the cheek-shields are uniformly granulated, and their external reflexed margin 

 is also ornamented with a row of tubercles and spines, which are visible everywhere 

 except in the centre of the anterior extremity. There is a very large tubercle on the 

 centre of the articular fold ; beside it at each side a rather smaller one, and surrounding the 

 latter several very small ones. The axis portions of the rings of the body have two rather 

 large tubercles beside the centre, and also two small ones externally at each side. An 

 elevated fold is seen on the lateral lobes, which terminates at the margin in a spine, and 

 which is covered on its surface with seven tubercles, alternately large and small. Towards 

 the anterior as well as the posterior part of this fold we perceive a transverse row of other 

 very small tubercles, and a second smaller row, corresponding with the anterior row, occurs 

 at the margin before the spine. These small spines are all of equal length, but the larger 

 ones become gradually longer towards the posterior part. The caudal shield is rather 

 smaller than the cephalic shield, covered by larger or smaller tubercles, and spiny at the 

 circumference ; the spines, of which there are six at each side, are equally long and equally 

 broad ; the fold which proceeds from the first ring of the axis becomes bent at the third 

 ring from the centre. 



* Emmerich only enumerates seven, but has omitted to notice the fact that both lateral lobes 

 were broken off from the fifth joint, and that thus the true number was not given. Compai'c his 

 figure and mine. 



