16 CARBONIFEROUS TRILOBITES. 



2. Phillipsia Colei, M'Coy, 1844. Plate II, figs. 1—10. 



Phillipsia Colei, M'Coy. Synop. Carb. Foss. of Ireland, p. IGl, tab. iv, fig. 6, 

 1844. 



— — Morris. Cat. Brit. Foss., p. 114, 1854. 



— — //. Woodw. Cat. Brit. Foas. Crust., p. 55, 1S77. 



Head-shield broadly-semicircular ; glabella but slightly elevated, the central 

 convexity not reaching to the front border, but separated by a broadly-expanded 

 margin which makes the head one third wider in front than at its posterior border ; 

 glabella marked by two short lateral furrows and by a small basal lobe on each 

 side, the neck-furrow is rather strongly marked, the neck-lobe is slightly broader 

 than the first free segment ; the posterior margin is divided obliquely by the 

 facial suture which runs in a very undulating line between the glabella and the 

 free cheek; eyes large, reniform, no facets visible; cheeks arched, somewhat 

 produced at the posterior angles, surrounded by a furrow parallel to the border ; 

 free segments nine ; axis very slightly arched, equal to its pleuras in breadth 

 anteriorly, but diminishing shghtly towards the pygidium ; pleurse faceted, 

 extremities slightly produced and recurved : pygidium semicircular, axis slightly 

 arched and composed of twelve coalesced segments ; pleuras only faintly indicated, 

 margin of pygidium smooth and slightly bevelled. Surface of head and body 

 generally (save the extremities of the pleuree) finely granulated. 



A detached hypostome found in the same piece of matrix with one of the 

 Survey specimens has been referred to this species. It is 7 mm. long and 4 mm. 

 broad. It is oblong in form ; the alse are very minute, the central lobe is gibbous 

 and ornamented with five raised concentric strias or wrinkles, irregularly disposed. 

 (See PI. II, fiiT. 6.) 



This well-marked species was named by M'Coy after the present Earl of 

 Enniskillen ; and, having only been found in Ireland, it has escaped the entangle- 

 ments of pateontological literature, and is in consequence without synonyms. 

 Although quite distinct from any other species of Phillipsia, it is marked by 

 excellent generic characters. 



In the pecuUar broad, smooth, circular border to the front of the glabella this 

 species approaches nearest to Ph. truncatula and Ph. EichwaJdi. It differs from 

 Ph. Derhiensis, in which the glabella is very gibbous and actually overhangs the 

 front border. But in the broad, short, and flattened form of the pygidium we 

 seem to lose the ordinary tail of the Carboniferous Trilobite and to find a strong 

 resemblance to the pygidium of Asaphus and Ogygia proper. This leads one to 

 observe that the form of the pygidium appears to be a less constant character and 

 of much less value for classification than the cephalic shield. 



