4 



BRITISH FOSSILS. 



behind ; the axis short/its length less than half that of the tall, com- 

 posed of two joints, an upper ring, which is very narrow in the middle 

 •and is produced downwards at the side, and a rounded terminal 

 joint. On the forward edge, and close to the axis on each side, is a 

 strong and prominent fulcral tubercle like those of the pleurse. The 

 flat limb terminates in four rather short teeth all directed backward, 

 the two lateral ones, though nearly equal in size with the others, 

 not being produced so far back. These teeth are broken off in the 

 specimen figured, but the description is taken from well preserved 

 specimens found.in North Wales, and apparently of the same species ; 

 the surface of the limb and of its teeth is finely striated across with 

 close waved lines. 



British Localities and Geological Position. — Lower Silurian ; 

 Desertcreat parish, Tyrone, in argillaceous schist, fig. 1. Bala lime- 

 etone, North Wales. 



EEMOPLEUEIDES LATEEISPINIFEE. 

 Fig. 2. 



Diagnosis. R. longiovatus, glabella maximd quam longd latiori, ad 

 frontem inter oculos angusta ; genis parvis, in spinas breves extensis; 

 thoracis axi latissimo, antice pleuram ter et plus superante, pleuris brevibuSy 

 septimo utrinque longe producto, fulcro appresso elevato; caudm axi abbre- 

 viato biannulato ; (margo omnino caret, ut in prcecedenti habendus.) 



Synonyms. R. laterispinifer^VoniiuOCYL (1843), I. e., pi. 1. fig. 2. M'Coy 

 (1846), Syn. Carb. Foss. Irel. 43. Corda (1847), Prodr. Bohm. Tril., 113. 

 t. 6. fig. 59 [mala]. 



Description. — Length fourteen lines, width eight lines. The 

 general shape and convexity, the size and form of the glabella, cheeks 

 and eyes, are the same as in the preceding description. But the 

 head is rather more than one third the whole length of the body, 

 and the width of the tongue-like front of the glabella (which could 

 not be accurately determined in the foregoing species), is somewhat 

 less than half that of the entire glabella. 



The axis of the body is in front nearly four times as wide as the 

 short pleurae, in the last ring it is only one third of this width, and 

 about twice the width of its pleura ; its segments are each tuber- 

 culate along their hinder edge, as in the last species, and show some 

 faint traces of granulation over the surface ; the seventh pleura 

 on each side is abruptly lengthened and produced backwards (not 



