ON THE STOCKDALE SHALES. 723 



have, so far, been discovered, but they are sufficient to show that the 

 species is clearly distinct from C. granulatus, Ang., C. conformis, 

 Ang., and 0. Roemeri, Schmidt (the forms which it most nearly 

 resembles), in the characters of the basal lobe and the details of the 

 ornamentation. 



Hor. Sj' Log. Eare in the PJiacops-glaher zone of Skelgill. 



AOIDASPIS EEINACEUS, n. sp. (PI. XYI. figs. 11, 12.) 



Length \ inch. Head twice as broad as long, front produced, 

 smooth; sides ornamented with several short spines. Glabella 

 tumid, the central portion broadest in the centre, flanked on either 

 side by two circumscribed lobes, of elliptical shape, the posterior 

 one being the larger. Eyes and course of facial suture not clearly 

 defined in the specimens. Posterior angles produced into long spines 

 curving outward and backward. Neck-lobe large, with lateral 

 tubercles, each giving off a stout short spine, and having a large 

 granule in its centre. Entire head ornamented with coarse granules. 



Body-rings 8 in one of the two nearly complete specimens dis- 

 covered, and 6 in the other less mature one. Axis with marked 

 tubercles at the extremities of the rings ; pleurae (omitting spines) 

 nearly twice as wide as axis, consisting of an anterior smooth por- 

 tion, and a posterior ridge ornamented with two granules on each 

 pleura. The ridge is bent back at the outer margin to form a long 

 slender spine at least as long as the body of the Trilobite. 



Tail having a short axis of two rings with prominent tubercles. 

 Limb ornamented with ten spines as follows : — two very short an- 

 terior ones on each side, succeeded by a very long pair connected 

 with the axis by raised ridges. Each marked with a tubercle. 

 Behind this is a short pair and, lastly, a larger pair, all of these being 

 directed backwards. 



This species resembles^, centrina, Dalm. ( = A. granulata^ Aug.), 

 from the same horizon in Sweden, but it differs from the latter, as 

 shown in Angelin's figure, in the following particulars : — 



The head has a produced front and a strongly granulated surface. 



The rings of the axis have large lateral tubercles instead of a row 

 of granules. 



The tail differs in the disposition of the s]3ines and the presence 

 of a connecting- ridge between the large spine and the axis. It is 

 true that Barrande has shown that the disposition of the tail-spines 

 varies in the same species ; but we possess a large number of tails of 

 our form in which the arrangement is constant. 



One of us has collected an Acidaspis from the Upper Brachiopod- 

 schists of OUeberg, in which the spines appear to be disposed as in 

 the present species. 



Hor. <Sf Log. Yery abundant in the zone of Acidasjns erinaceus 

 at Torver Beck. 



Haepes judex, n. sp. (PI. XYI. figs. 13, 14, 14: a.) 



Length probably |-1 inch. 



Head semicircular, surrounded by a broad, very convex limb, of 

 horse-shoe shape, prolonged backward into a blunt point. 



