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SILURIAN TRILOBITES. 



what clavate form, the truncate ends being oblique. The two terminal ones close so 

 completely behind the axis that the suture is soldered, and they appear as a single rectan- 

 gular plate, with a terminal notch only. The whole tail is gently and regularly convex, 

 and the appearance thus given is very peculiar. 



Locality. — Caradoc Slate of Tramore, County Waterford (Mus. P. Geol.). 



Amphion benevolens, n. sp. PI. VI, fig. 31. 



A. minor, capite {solum eognoto) lente convexo, latimarginato, margine fronted! incras- 

 sato nec crenulato. Glabella lente convera antice latior, lobis longis transversis, antico 

 abbreviate triangularis vix plus quam dimidium frontis ejjieiente ; sulco centrali nullo. Ocu/i 

 retrorsi, d glabella paullum reu/oti. Reliqua absunt. 



Much more nearly like the Russian species than the one above described. A. bene- 

 volens, named in honour of Mr. Nevins, of Waterford, differs from that species in its pro- 

 portions, and in the presence of a plain, thickened, anterior margin instead of the crenulate 

 border visible in the Scandinavian fossil. It is about the same size. We have only the 

 glabella and a part of the cheeks, which show the eye to have been also very much nearer 

 the glabella than in the species just quoted. 



Head seven lines long and about fourteen wide, semicircular, a little pointed in front, 

 gently and regularly convex, the glabella being just as long as broad above, and tapering 

 slowly behind — the axal furrows quite straight. A thick margin runs round the front, 

 quite free from corrugations, and with a small tubercle in the centre, the division between 

 this margin and the glabella being feeble for the extent of the forehead-lobe, which occupies 

 rather more than half the whole width of the glabella in front, and has a pair of very 

 oblique, faint, straight furrows to bound it. Outside this the marginal furrow is as deep (in 

 the cast, which is all we possess) as the abrupt axal furrows of the head. The middle and 

 basal furrows are long, reaching more than one third across the glabella ; the middle one 

 straight at first, then gently decurved, the lower one quite straight, and all of them deepest 

 at their inner termination. The neck-furrow rises considerably toward the middle, so as 

 to make the basal lobes cuneate, but neither the neck-segment nor any of the lobes are 

 tumid. All partake of the regular and gentle convexity of the head. 



The eye is placed opposite the median lobe ; it is small, but elevated, and surrounded 

 by a rather deep furrow, and it is only about twice as far from the glabella as from the 

 neck-furrow (in A. Fischeri it is three or four times as remote). 



Locality. — Caradoc Slate of Newtown, Waterford, in company with Phacops Jamesii, 

 described at p. 32. 



