52 F. R. Coicper Reed — New Bala Trilohites. 



in the smaller size of the frontal lobe, in the presence of the " side- 

 tubercles," in the greater width of the anterior border, in the 

 triangular portion of the cheek that lies in front of the ocular 

 ridge not being vertical, in the greater depth of the terminal pits, 

 in the smaller width of the cheeks, in the irregular disposition of 

 the tubercles on the glabella and cheeks, in the presence of two 

 tubercles on the eye-ridge, and especially in the spatulate anterior 

 process. These differences appear to me to be quite sufficient to 

 justify a new species being formed for the reception of the Irish 

 Cybele; and from the locality near which it was found it may appro- 

 priately be designated Cybele tramorensis. 



Dimensions. 



Length of glabella from neck furrow to anterior extremity '350 inch 



Breadth of glabella at level of the second lobes ,, -275 inch 



Greatest width of cheek (measured along posterior border) "470 inch 



Distance between "terminal pits" '350 inch 



Length of anterior '-spatulate process" (measured from anterior extremity 



of glabella) -175 inch 



Distance of eye from side of glabella (measured along ocular ridge) "250 inch 



Trinucleus Tiiberniciis, n. sp. (PI. III. Figs. 2-7.) 



This new species of Trinucleus is extremely abundant in that 

 portion of the Bala series which is exposed at Newtown Cove, 

 near Tramore. The average length of this form is a little more 

 than half an inch ; a rolled-up specimen measured '6 inch, but 

 some of the head-shields found were larger than that of this 

 individual, while a few were smaller; but these differences may 

 only be due to age. The head-shields, which are by far the 

 commonest part of the trilobite preserved, very rarely have any of 

 the body-rings attached. The head-shield is rather longer than the 

 thorax and pygidium together, according to the above-mentioned 

 rolled-up specimen, but in those individuals in which the head- 

 shield has a semicircular outline it is rather shorter. 



There appear to be two forms of this species which are 

 characterized by the shape and certain features of the head-shield. 

 In one form this part has a slightly pointed front and approaches 

 a parabolic shape. In the other form it is broader and semicircular. 

 Certain other differences in the length of the glabella, the sulci in 

 the fringe, and lateral spines will be severally pointed out in the 

 description of these parts. Probably these two forms represent the 

 sexes, the pointed one being the male (?). 



The head-shield in the male is less than twice as wide as long, but 

 in the female the width is to the length as 9:4. The glabella 

 consists of a prominent globular frontal lobe set on a narrow basal 

 stalk. This large globular frontal lobe invades more than half 

 the width of the fringe, and in the male slightly overhangs also 

 the other half. It bears a central tubercle. Behind this lobe the 

 glabella is sharply contracted to form a narrow parallel-sided stalk, 

 about half the width and less than half the height of the frontal lobe, 

 but equal to it in length. This stalk-like portion has two pairs of 

 small transversely elongated lobes. The anterior pair is situated 



