2; 



BRITISH FOSSILS. 



Description. — An inch long, and five and a half lines wide, 

 generally convex, of a long ovate form, blunt and rounded in front, 

 narrow and pointed behind. The head occupies not quite one third 

 of the length, and is considerably wider than the body ; it is chiefly 

 composed of the large, smooth and convex glabella, which is widely 

 urceolate, the sides strongly arched outwards, so as to form a trans- 

 verse broad oval, exclusive of the produced and narrow tongue-like 

 front. The produced front is broken off in this specimen, but 

 doubtless existed, as in the other closely allied species ; we have 

 indicated its shape by dots. This contraction of the glabella in front, 

 so characteristic of the genus, is due to the excessive prolongation of 

 the eyes, which would meet in front, but for this narrow projection. 

 They completely encircle the sides of the glabella, separated from it 

 only by a narrow rim or eye lobe, and extend their course back- 

 wards into the neck furrow, approximating below as th-ey do in 

 front, and indenting a little the base of the glabella. The eyes are 

 of equal width throughout, and are smooth externally, but when 

 decorticated show a closely facetted surface. They are subtended 

 by a raised border along their lower edge. 



The wings or free cheeks are small and subtriangular, extending 

 at least as far as the eyes do in front (see fig. 1, a); they are striated, 

 have no distinct border, and are prolonged behind into a short and 

 slender spine, which is directed a little outwards, and reaches as far 

 as the third body segment. The eye line is not traceable in front, 

 behind it runs, as in all the genus, vertically beneath the eye, and 

 consequently ends close to the axal furrow. The neck segment is 

 not quite so broad as those of the body, and is separated from the 

 glabella by a sharp furrow. 



[At fig. 5, we have represented the hypostome either of this or of 

 one of the two following species. Colonel Portlock has figured this 

 specimen in a reversed position,* as possibly the internal cast of the 

 head ; but it is clearly an hypostome, and a comparison of its 

 characters with those of another species of Remopleurides, figured 

 by M. Corda in his work on Trilobites, pi. 6. fig. 58, enables us with- 

 out doubt to refer it to this genus. From its size it is probably 

 that of one of the three species represented on our plate ; and it was 

 found at the same locality with them in Tyrone. 



It is four lines broad, and two lines high, nearly rectangular, with 

 the base very broad and quite straight, and its outer angles elongated ; 

 it then contracts a little in width, and is strongly notched on the side 

 * Report, Tyrone and Londond., pi. 24. fig. 10. p. 470. 



