38 CARBONIFEROUS TRILOBITES. 



wliicli is seen on the upper surface of tlie crust, and hence that in the two 

 conditions they might appear different fossils." 



15. Griffithides calcaratus, M'Coy, sp., 1844. PL VII, fig. 13. 



GrBiFFiTHiDES CALCAEATus, M'Coy. Synop. Carb. Foss. Ireland, p. 160, pi. iv, 



fig. 3, 1S44. 



— — V. von Moller. Trilob. der Steinkohl., p. 19, 1867. 



— MTJCEONATTJS, S. Woodw. Cat. Brit. Foss. Crust., p. 37, 1877. 



This species was founded by Prof. M'Coy. in 1844 for a specimen from Ireland,^ 

 of which he figures the head only, but describes the head and tail also. We have 

 not been so fortunate as to see the original of M'Coy's figure, but we give his own 

 description as follows : 



" Cephalothorax semi-oval ; glabella smooth, ovate, most convex in the middle 

 of its length ; cheeks small, triangular, flat, smooth ; wings strongly striated, 

 broad, prominent, rounded, terminating posteriorly in long flattened spines ; eyes 

 moderately lunate (smooth ?), connected with the glabella by a nucleus on each 

 side ; pygidium with a smooth margin, each segment with a row of very minute 

 granulations. 



" This beautiful species is most nearly allied to the G. longispinus of Portlock, 

 but is at once distinguished by its smooth cheeks ; the eyes, also, in the present 

 species, are differently formed and placed, and the glabella is much smaller and less 

 prominent in front. Length of glabella five lines ; greatest width three lines ; 

 width at base one line ; width of cephalothorax seven lines ; length of eyes one 

 and a half lines ; width one line ; length of posterior alar spine three lines. 



" The pygidium has a broad, smooth margin or limb, in which it diifers from that 

 of G. longispinus, in which the segments are extended to the margin. There is a 

 single row of very minute granules on each segment. Width of pygidium five 

 lines" (op. cit,, p. 160). 



Although I placed G. calcaratus in 1877 as a synonym under G. 7nucronafns, 

 I find that neither the description nor figure admit of its being so disposed of, and 

 I therefore give it on M'Coy's authority. 



Valerian von Moller says of Griffithides calcaratus : "M'Coy only figures the 

 cephalothorax. It is nearly related to Fh. cjlohiceps^ Phill., but is distinguished 

 from this species by the very inferior size of the glabella, and by the long, flattened 

 cheek-spines ; and from another Trilobite, Ph. longiceps, Portl. (= G. longisjunuSf 

 Portl.), with which it is also nearly connected, it differs in its very narrow glabella 

 and the wide flattened border around the pygidium (op. cit., p. 19)." 

 * Said to be from the Upper Limestone, Eouglian, Dungannon. 



