80 SILURIAN TRILOBITES. 



and is very prominent and elevated, but not broad ; neither of our specimens show its full 



width. 



The strong convexity of the great eye-like lobes suggests some such name as the 



above. 



Locality. — Caradoc Slates of Sholes Hook, Haverfordwest (fig. 27, Mus. P. Geology), 



Applethwaite Common, Westmoreland (fig. 28, Woodwardian Mus.). 



Amphion, Pander, 1830.* 



Head short, transverse, without spinose angles. Glabella nearly rectangular, with 

 three pairs of furrows, the front pair generally approximate on the anterior margin, and 

 always enclosing a very small forehead-lobe, often narrower than the glabella. Eyes 

 small [reticulate, Angelin] ; facial suture behind the eyes ending on the exterior margin a 

 little in advance of the rounded angles ; labrum entire, pointed, convex, margined all 

 round ; body with fifteen to eighteen rings, the pleura? without grooves ; tail of few 

 segments, the axis short, the pleurae with free terminations [includes Pliomera of Angelin, 

 1852]. 



Amphion is just one of those genera which show the near connection between the 

 Cheirurida and Calymene, to which it is allied by the elongate form, numerous body- 

 segments, glabella not widened in front, and facial suture ending nearly in the angles. 

 On the other hand, it is like Zethus and Cybele by the grooveless pleurae and free 

 segments of the tail, which extend beyond the margin as in those genera, and close behind 

 the shortened tail-axis ; also by the entire labrum. 



From both groups the peculiar shape of the glabella and the numerous unfurrowed 

 pleurae distinguish it. The typical species is the Asaphus Fischeri of Eichvvald, which was 

 called Calymene poly toma by Dalman. Pander established the genus Amphion, but again 

 altered the specific name. In A. Fischeri there are eighteen body-rings. 



Amphion pseudo-articulatus, Portloclc. PI. VI, figs. 29, 30. 



Amphion pseudo-articulatus, Portloclc. Geol. Itep. Londond. Tyrone, pi. iii, fig. 5, 



1840. 



— — Salter, in Morris's Catal., 2nd edit. p. 99, 1854. 



— — Id. Siluria, 2nd ed., p. 537, 1859. 



A. triuncialis, lonyus, axe ylabelldque convexis, fronte haud contracto. Caput semi- 

 circidare, margine angmto. Glabella subparallela, convexa, lobis brevibus, subradiatis, 

 antico quam glabella lato, transverso, lineari. Oculi retrorsi, prope glob ell am positi. 

 Thorax segmentis 17, axe convexo. Cauda expansa, pleuris subclavatis 5, duobus termi- 

 nalibus post axin abbreviatum subplanum omnino connatis. 



* 'Beitrage zur Geognos. des Russicli. Reiclies,' Petersburg, 4to. 



