F. R. Cowper Reed — New Bala Trilohites. 51 ■ 



of the spatulate process. This marginal tubercle corresponds with • 

 the "side-tubercle" of Schmidt, which is present in must species' 

 of Cyhele, but is wanting strangely in C. coronata, to which the 

 Irish form is most closel}^ allied. 



Close beneath the posterior outer slope of the ridge leading up to' 

 the " side-tubercle " is a deep circular pit, called by Schmidt the 

 " terminal pit." It lies at the anterior end of the axal furrow, 

 and is a most conspicuous object on the liead-shield. According to 

 Schmidt it corresponds with a similarly-sitixated pit in some species . 

 of Cheininis, and is concerned in the attachment of the hypostome. 

 The pit is, in the form under description, bordered posteriorly by. 

 a strong horizontal ridge — the ocular ridge — which runs outwards 

 to the eye, at right angles to the axis of the glabella, and opposite 

 to the first side-furrow. It is probably parallel to the posterior 

 margin of the head-shield, but of this one cannot be quite certain 

 owing to the imperfect preservation of that part. This ocular ridge 

 has a row of minute pits close along the base of each side, and it 

 also bears two large tubercles. 



The anterior edge of the cheek runs outwards and backwai'ds in 

 a nearly straight line to meet the outer extremity of the ocular 

 ridge at the small eye which is situated at a distance from the side 

 of the glabella nearlj'- equal to the width of the frontal lobe. The 

 triangular space thus enclosed between the " terminal pit," the 

 ocular ridge, and the front border of the cheek is inclined slightly 

 downwards and forwards. It bears a central tubercle, and is also 

 granulated and minutely pitted. Behind the ocular ridge lies the 

 main portion of the cheek ; its inner corners are almost rectangular, 

 but its outer side has an outward as well as a backward trend.' 

 from the eye, so that the width of the cheek measured along its 

 posterior margin is more than half as much again as that of the 

 glabella. At the bluntly pointed outer posterior angle the cheek ist 

 leather sharply bent down, and this downward bend seems to extend 

 forwards some way along the outer side ; otherwise the cheek is 

 almost flat and horizontally extended. On its surface it carries' 

 two or three large tubercles and many smaller ones, in addition to 

 numerous minute pits. 



In the absence of any portions of the thorax or pygidium, a fuller' 

 description of the species at present is impossible. 



On reviewing the previously described species of Cyhele, one 

 sees that this Irish form more closely approximates to C. coronata 

 (Schmidt) than to any other. With this species, which occurs in 

 Co (Brandschiefer) of Estland, it agrees in the axal furrows being 

 very shallow, in the position and characters of the side furrows, in 

 the strong horizontal eye-ridge with side punctures at the level of 

 the first side-furrow, in the position of the eyes, in the general shape 

 of the cheeks, and in the relative dimensions of the various parts. 

 If my interpretation of the origin of the spatulate process is correct, 

 the long "crown" of spines in C. coronata may also be regarded as. 

 a point of similarity. The Irish form, however, differs from this 

 species in the glabella not being strongly arched forward in front, 



