110 BRITISH CAMBRIAN TRILOBITES. 



Genus PARABOLINELLA, Brogger. (Addendum to p. 70.) 



To complete the account of the British forms refeiable to Olentis sensu lato I 

 add here a description of the very poor specimen which Salter called Gdnocoryphe ? 

 simplex. I have no doubt that it belongs to the genus Parabolinella, but, owing 

 to its very imperfect condition, it has no claim to be considered as the type of a 

 distinct species. It may very possibly belong to one of the species already described . 



1. Parabolinella simplex (Salter). Plate XIII, fig. 6. 



1866. Conocory phe ? simplex, Salter, Mem. Geo]. Surv., vol. iii, p. 306, pi. v, fig. 17. 

 1878. Ellipsocephalus sp., Cat. Camb. and Sil. Foss. Mus. Pract. Geol., p. 12. 



The very imperfect specimen described by Salter as Conocoryphe ? simplex 

 shows only the middle of the head. 



The glabella is prominent, short, and square, but somewhat expanded near the 

 base, and it is separated from the margin by a space which is three or four times 

 as wide as the margin. According to Salter the glabella is without lobes; but, 

 althongh they are very imperfectly shown, there are, on the left-hand side of the 

 specimen, indications of at least two glabellar furrows. The eye is about half-way 

 between the anterior and posterior margins, and distant from the glabella about 

 half the width of the latter. The facial suture runs inwards from the anterior 

 margin to the eye and thence outwards to the posterior margin, which it cuts at a 

 distance from the axial furrow rather less than the width of the glabella. The 

 margin is narrow, flat, and, so far as it is shown, very uniform in width. 



Dimensions. — Length of the head 10*5 mm., of the glabella 7*5 mm. (measured 

 on the counterpart, which is rather more complete posteriorly than the figured 

 specimen). 



The short, square glabella, the narrow, uniform margin, the width of the frontal 

 limb, and the course of the facial suture are the characters which lead me to place 

 the specimen in Parabolinella. The faintness of the glabellar furrows seems to 

 be due simply to the state of preservation. 



Both Reed 1 and Brogger 2 have referred it to Cyclognathux ; but they appear to 

 have been misled by Salter's figure, which is not very accurate. It is to some 

 extent a restoration, but the original specimens, an internal east and its counter- 

 part, are in the Geological Survey Museum. From them it is clear that the facial 

 suture runs inwards from the anterior margin to the eye, instead of outwards as 



1 Geol. Mag. [4], vol. vii (1900), p. 255. 



2 Verb. d. Euloma-Niobe-F&una,, Nyt Mag. f. Naturvid., vol. xxxvi (1897), p. 200— separate copies 

 (1896), p. 37. 



