﻿CALYMENE. 



99 



is narrow, compared with the width of the sides, and seven- or eight-ribbed. The sides 

 have six ribs, strongly interlined throughout, and arched outwards ; and the general shape 

 of the tail is more transverse, ovate, and less triangular than in either the Dudley or 

 the Caradoc species. 



Locality. — Llandeilo flags of S. Wales, abundant at Llandeilo ; at Lann Mill, 

 near Narberth, &c. Fig. 1 3 is from a very perfect specimen observed by Sir H. De la 

 Beche, and of which a cast only of the external surface is preserved in the Mus. P. 

 Geology. The original is, I believe, in the rich cabinet of Mr. J. E. Lee, of Caerleon ; 

 and is the finest known. 



Calymene Tristani, Brontjn. PI. IX, figs. 15 — 18. 



Tristan, Journ. des Mines, torn, xxiii, page 21. 1807. 



Calym. Tristani, Brongniart. Cr. foss. 12, pi. i, fig. 2, a — k. 1822. 



— — Schlotheim. Nachtr. ii, 14, 2, 23, 2, and 40, tab. xxii, fig. 5, 1823. 



— — Balman. Pal^ad., G2, 3. 1826. 



— — Emmerich. Dissert, 39, 4. 1839. 



— — Milne-Edwards. Crust, iii, 320, 5. 1810. 



— — Barmeister. Org. Trilob., tab. 2, figs 7, 8, 1843, and Ray Ed. 



p. 40. 184G. 



— — Salter. Quart. Geol. Journ., vol. xx, pi. xv, fig 5. 1864. 



Calymene Tristani is a fossil belonging to the French, and not the British, Silurian fauna. 

 But imperfect heads of this species are certainly found in the quartzose strata of Gorran 

 Haven, near Mevagissey, Cornwall; and the tail, fig. 17, is found in company with 

 several other French fossils in the now famous Budleigh Salterton pebble-bed. 



Our specimens from Gorran Haven, figs. 15, 16, show only the glabella and front of the 

 head. The former is short, and wider than long, with the base broad, so as to form a nearly 

 equilateral triangle. All the lobes deeply marked, and oblique forwards ; the basal lobes 

 triangular, the middle ones nearly linear ; the upper ones strong for the genus. The cheeks 

 highly convex, separated from the glabella by broad but shallow axal furrows ; which at 

 the base expand over a triangular flattened depressed space (fig. 18) analogous to the cor- 

 responding portion in Homalonotus, see p. 104, line 6. The eyes are placed forward op- 

 posite the upper glabella lobes. The cheeks strongly margined exteriorly. The front is 

 produced, very convex and recurved ; and the space from the front of glabella forwards is 

 nearly equal to the length of the glabella itself. We have not the body, — which in foreign 

 specimens has a broad axal lobe and greatly decurved convex pleurae. The axis of the 

 subtrigonal tail, fig. 17, is highly convex and broad, of six or seven rings, and an appendix 

 which reaches the end. The sides have five strong ribs interlined for nearly their 

 whole length. I do not consider our British specimens sufficient to afford a regular 

 diagnosis of the species. 



