32 TRILOBITES OF GIRVAN. 



Specific, Characters. — Glabella broad, flattened, consisting of a transversely ellip- 

 tical portion between the eyes and a rounded anterior tongue not bent down, nearly 

 or quite as long as the posterior portion and slightly expanding anteriorly with a 

 rounded non-truncate extremity and a faint median longitudinal groove on its 

 surface. Glabella marked between eyes by three pairs of furrows placed about 

 equal distances apart, none reaching the sides of the glabella, but all extending 

 inwards to about the same distance and to such an extent as to leave only a narrow 

 band down the centre. Anterior pair of furrows short, obliquely directed back- 

 wards and inwards, and at the level of the anterior end of the eyes. Second pair 

 longer, nearly horizontal or slightly curved, and situated opposite the middle of 

 the eyes. Posterior pair shorter than the second pair, but parallel to it, and a 

 little in front of the base of the eyes. 



Occipital furrow deep, strong, gently curved, more marked than the glabellar 

 furrows. Occipital ring rounded, of moderate width, with central tubercle. Surface 

 of glabella (including tongue) and of occipital ring crossed by fine transverse 

 slightly undulating parallel lines which bend forward at the sides of the glabella. 

 Eye-lobes strongly curved, semi-annular, narrow, extending from base of glabella 

 to base of tongue, embracing posterior part of glabella, indenting its base on each 

 side, and marked off by strong furrow. 

 Dimensions (type specimen). — ■ 



Length of glabella (including tongue) . . 5'0 mm. 



Width of „ between eyes . . .5*0 „ 



Length of eyes .... 2 - 5 ,, 



Distance between bases of eyes . . 2'5 „ 



Remarks. — This species was founded by Nicholson and Etheridge on several 

 head-shields from Balclatchie, but three distinct forms were included by them 

 under this one name. Their description of the species agrees best with the first 

 figured specimen, but the others are completely different, and they must be 

 removed from association with it. The type, therefore, of B. barrandei is fig. 1 3 of 

 pi. x in Nicholson and Etheridge's Monograph, and the amended description of 

 this form is as given above. 



The three pairs of glabellar furrows and the median one on the tongue are 

 distinctive features. The tongue in some specimens has a wide spatulate shape, 

 but this may be largely due to its flattening out by crushing. The remarkable 

 ornamentation of the surface of the glabella, though clearly visible in the type, 

 was not noticed by Nicholson and Etheridge. It is not present in any of the other 

 specimens figured by them as belonging to this species; and these in fact possess 

 a completely different ornamentation as well as other distinctive features, for 

 which reasons three of them have to be removed into another species designated 

 B. correctus, sp. nov. (q. v. postea), and one (figured by them on pi. xi, fig. 1(5) 

 into a third species. 



