122 



Proceedings of the Royal Irish Academy, 



with the preservation. If the upper portion has been stripped ofp^ 

 two rows are to be seen separated from the remainder by a groove. 



Horizon and Localities. — Killey Bridge beds. Little River^ 

 Tirnaskea, Killey Eridge. 



Yar. elongatus (= Tr. elongatus Portl.). 



Closely allied to var. PortlocMi, but having the glabella more pyri- 

 form and the cheeks longer than broad. 



Sorizon and Localities. — Xilley Bridge beds. Little River, Tirnaskea. 



Yar. arcuatus. 



Glabella. — Ovoid, encroaching upon the border of the head-shield ; 

 furrows absent or imperfect. 

 Cheelvs. — Broader than long. 



Border. — Bows of punctures fewer in number than in var. Portlochii\ 

 two to three rows in front of glabella ; while near genal angles, which 

 are rounded or somewhat pointed, there are four rows of punctures, 

 with an inner row of slit-like furrows encroaching upon the outer 

 margins of the cheeks. Posteriorly the margin of the head-shield is 

 not straight, but curves forward at the extremities ; hence the genal 

 angles are in advance of the rest of the margin. 



This form appears to be the same as one mentioned by Portlock as 

 being intermediate in character between his Tr. latus and Tr.fimhriatus ; 

 but these two forms appear to be identical. 



Horizon and Locality. — Killey Bridge beds. Little Eiver, Tirnaskea. 



Trinucleus seticornis His. 



Head. — Shield semicircular, with punctate border, broad and folded 

 ventrally at right angles to j^lane of the thorax ; two anterior rows of 

 tubercles, separated from the rest by a pronounced groove. Genal 

 angles with long spines. 



Glabella. — Grlobose, separated anteriorly from cheeks by deep 

 furrow ; glabella furrows, three in number, including neck furrow. 



Cheeks. — Prominent, each with tubercle at the summit. 



This description agrees on the whole with that of Portlock ; but 

 his figure shows neither the folding of the border nor the groove, 

 which is, however, only visible where the upper surface is stripped off. 



Horizon and Localities. — Killey Bridge beds. Little River, Tirnaskea. 



Dionide cfr. euglyptus Ang. 



Head. — Semicircular to triangular in outline ; genal angles spined. 

 Glabella. — Circular, inflated with two furrows, starting from the 

 neck furrow, and running forwards and sideways so as to cut off 



