722 ME. J. E. MAEE AOT) DE. H. A. KICHOLSON 



The Lake-district form, so far as we can make out from the 

 somewhat scanty material we possess, corresponds in every particular 

 with specimens of P. mucronatiis obtained by one of us from the 

 Tipper part of the Brachiopod-schists of Westrogothia, which occupy 

 a corresponding position to that of the Stockdale Shales. It seems 

 to differ from the poorly preserved form described by Salter (Mon. 

 Brit. Tril. p. 46). 



Hor. ^ Log. Heads and tails of this Trilobite are not rare in the 

 zone of Amioyx aloniensis at Browgill. A fragment of tail, possibly 

 referable to the same species, has been discovered in the Barren Band 

 at SkelgiU. 



CflEiETJETJs b]3iuceo:n-atus, Murch., var. nov. acais^thodes. (PI. XYI. 

 figs. 7, 8.) 



Head less than J inch long. Glabella with basal lobe circum- 

 scribed, the furrow well marked in front, shallower behind. Middle 

 and upper furrows as in the normal form. Eye opposite the upper 

 lobe. Facial suture cutting the posterior margin far forward. 

 Posterior angle of the cheek produced into a curved spine at least 

 as long as the glabella. Tail, with a short axis possessing two 

 well-marked fiuTows. Limb slightly furrowed, the border produced 

 into three prominent spines on each side. 



This form diifers from the Wenlock species not only in possessing 

 the elongated spines to the cheek and tail, but also in the forward 

 position of the eye, and the point where the facial suture cuts the 

 lateral margin. In these respects it agrees with a specimen from the 

 Llandovery rocks of Llandovery, figured by Salter (Mon. Brit. Tril. 

 pi. V. fig. 4), the original of which is in the TVoodwardian Museum, 

 which also may have possessed the elongated spines. We suspect 

 that several forms which have been referred to Murchison's species 

 are really distinct, but in the meantime prefer to keep the well- 

 marked little Trilobite from the Stockdale Shales (which must have 

 attained a length not much exceeding one inch) under this specific 

 name, merely giving it a varietal distinction. 



Hor. ^' Log. Zone of FJiacojJS glaher, Skelgill ; zone of Ampyx 

 aloniensis, Skelgill and Browgill : zone of Acidaspis erinaceus, 

 SpengiH ; Calcareous band, Austwick Beck. 



ChEIETJETJS (PsErnOSPHiEEEXOCHrs) IIOEOIDES, n. sp. (PI. XYI. 



figs. 9, 10, 10 a.) 



Glabella, length 5 lines, width 4 lines, widest in the centre. 

 Xeck-lobe not preserved. Basal lobe circumscribed, elliptical, rather 

 broader than long, occupying more than one third the entire width 

 of the glabella, basal furrows very deep and defined : middle furrow 

 moderately deep, extendiug about ^ of the way across the glabella ; 

 upper furrow much shorter and not so strongly defined. Middle 

 lobe shorter than basal, and slightly larger than upper. Frontal 

 lobe short. 



The whole glabella very convex, and uniformly marked with very 

 large granules, between which are smaller ones and a third series 

 yet smaller. 



Only two imperfect specimens, displaying portions of the glabella, 



