lia G. F. MATTHEW: ILLUSTEATIOlSfS OF 



Facial, suture. — This cuts obliqiiely across the anterior marginal fold, at the beginning 

 of the lateral third, where the fold has already begun to bend rapidly toward the posterior 

 margin ; after crossing the fold, the snture runs along the side of the cheek and curves 

 outward toward the posterior angle. 



Glabellar furrows. — The describer of the species states that there are none, or that they 

 are but slightly marked, without specifying their number or position. It is true that on 

 many heads they are obscure, but on others they are sufficiently distinct to be easily seen. 

 The posterior pair originates at a point on the side of the glabella more than two-thirds 

 from the posterior end, and arches backward at an angle of 45°, nearly attaining the 

 summit of the glabella, and terminating quite close to its end. The second pair is less 

 distinct, and is also directed backward, but less decidedly than the posterior pair, reaching 

 about half way to the summit of the glabella ; this pair is about as far from the front, as 

 the posterior pair, at their oviter ends, is from the back of the glabella. The anterior pair 

 of furrows is both faint and short, often to be detected only as shallow depressions on the 

 surface of the glabella. 



SculjÉure. — The outer surface is smooth. Some tests are distinctly granulated on the 

 inner surface ; these markings are sometimes large enough to be seen by the naked eye, 

 but generally cannot be resolved without a lens ; they are largest on the higher parts of 

 the occipital ring and glabella. It is also on the inside of the test that the ocular ridge 

 and its ramifications can be seen to the best advantage; on the oiitside of the shield both 

 are but faintly visible. On tests that are unusually well preserved, very fine granulations 

 of the outer surface may be detected with a lens. 



THORAX. 



Only eight segments of this region of the body are known. 



Axis. — The few rings of the axis preserved indicate that it was comparatively narrow ; 

 the rings are well arched, rounded and smooth. 



The pleurœ are strongly geniculated at the fulcrum, which is about half way from the 

 axis. There is a wide and deep concave furrow on the inner half of each pleura ; but be- 

 yond the fulcrum, the furrow narrows rapidly, and the bounding ridges slope away from 

 it on each side : the furrow ends rather abruptly on the median line, before reaching the 

 extremity of the pleura. The pleurœ are not so strongly angulated at the middle of the 

 thorax as near the head. 



PTGIDIUM. (Fig. 24.) 



Length, about 10 X 20 mm. Broadly lenticular, and its width is twice its length. 



Axis narrowed posteriorly, scarcely reaching the extremity of the j)ygidium. Can-ies 

 three rings, beside the articulating facet ; third ring faintly defined ; terminal lobe rounded 

 at the extremity and descending abruptly at the end. Each of the rings is indented with 

 a sharj) stria, nearly half of its length and parallel to its course. Each of these strise on 

 the outside opposes a more distinct groove on the inside of the test. 



Lateral lobes. — The side lobe of the pydidium bears three ribs, beside the half rib in 

 front ; the third rib is only faintly raised above the general surface ; a narrow, faint fur- 

 row, or stria, may be seen to pass outward from the posterior side of the inner end of the 



