A NEW CAMBRIAN TRILOBITE. 139 



pressed spine, which extends across the anterior joint, appears to 

 belong to the posterior joint of the thorax. The side lobes are con- 

 vex, and are of nearly equal width except at the back. The margin 

 is entire, except that it is notched behind at the axial line. 



Fragments of the hypostome have been found, but are not suffi- 

 cient for description. 



Sculpture. The surface of the marginal fold of the movable cheek 

 is marked by widely spread, anastomosing, raised lines; along the 

 front margin of the shield, close to the edge, a few of these lines 

 appear, but are closely crowded, both on the free cheek, and on the 

 middle piece of the head shield; along the genal spine the raised lines 

 run diagonally downward from the outer to the inner margin; along 

 the posterior border of the head shield there are crowded raised lines,, 

 as along the anterior border. On the doubleur the lines are crowded 

 and more distinct. The edges of the ring of the l-achis show similar 

 crowded wrinkles; on some pleura? there is a narrow band, or trans" 

 verse wrinkling on each side of the pleural groove; in . others the 

 wrinkled band covers the whole under surface, and the wrinkles or 

 raised lines become gradually drawn out in V-shaped lines along the 

 pleura, so that towards. its extremity they become parallel to the axis 

 of the pleura. On the pygidium there are raised lines, but finer and 

 more crowded, and parallel to the posterior border. 



Size. Length of the middle piece of the head about 70 mm. 

 Width in front 110 mm.; at the eyelobe 95 mm. at the posterior 

 angle about 90 mm. Length of the cord of the anterior extension of 

 the facial suture 25 mm.; of the eyelobe 17 mm.; of the posterior 

 extension about 20 mm. Length of glabella and occipital ring about 

 55 mm. width at third furrow 25 mm. at the first furrow 32 mm. 

 Length of movable cheek 60 mm. and with general spine about 175 

 mm., width at the front 25 mm., at the back of the eyelobe 37 mm., at 

 the posterior margin about 35 mm. Length of the pygidium about 

 20. mm. ; width 27 mm. 



Horizon and locality. Occurs in a very fine, greenish-grey shale,, 

 resting on volcanic ash rock, seen in a railway cutting at Manuel's 

 .Station, Conception Bay, Newfoundland. What appears to be the 

 original surface of the ash rock in Cambrian time was uneven, and the 

 fine mud of the shale settled into the inequalities of the surface. Al- 

 most directly upon the old rock surface, there is a layer of a few inches 

 of shale abounding with the detached parts of this trilobite ; the tests 

 are confusedly crowded together, flattened and somewhat distorted in 

 the shale, and are accompanied by a large Hyolithes. 



