BRONTEUS ANDERSON! 87 



of the Keisley examples of flu's species was pointed out by tin,' present writer in 

 1896 (op. cit). But only the head-shield was known at that time. The curious 

 group of furrows in front of the glabella recalls those in Agraulos ? globosus, Walcott, 

 from the Cambrian of the Eureka district, Nevada. 1 In the shape and characters 

 of the glabella and cheeks there is also a resemblance to Bathyurus tuberculatus, 

 Walcott, 2 from the same horizon and region. But on the whole the head-shield 

 with its short swollen glabella, and the thorax, so far as they are known, seem to 

 link this form more with species of Menocephalus (e. g. M. minutus, Nieszk. 3 ) than 

 with any representatives of Cyphaspis or any other genus, and therefore the 

 sub-genus Tomquistia may preferably be placed under the genus Menocephalus. 



Collection. — Mrs. Gray. 



Horizon and Locality. — Balclatchie Group (Llandeilo) : Balclatchie. 



Family Beonteid^. 

 Genus BRONTEUS, Goldfuss. 

 J. Bronteus andersoni, Nicholson and Etheridge, 1879. Plate XII, figs. 8 — 11. 



? 1876. Bronteus brongniarti, Armstrong and Young, Cat. West. Scot. Foss., p. 15. 

 1879. Bronteus andersoni, Nicholson and Etheridge, Mon. Silur. Foss. Girvau, fasc. ii, p. 162, 



pi. xii, figs. 3 — 5. 

 1899. Bronteus andersoni, Mem. Geol. Surv., Silur. Rocks Brit., vol. i, Scotland, pp. 536, 542, 



672, 688. 



Specific Characters. — Head transverse, semicircular (?), flattened. Glabella 

 weakly convex, broadly club-shaped, consisting of an almost parallel-sided neck 

 about half the entire length of the glabella, and of an expanded anterior portion 

 nearly twice the width of the neck and projecting laterally so as to overhang the 

 cheeks. Frontal lobe Avith anterior lateral angles measuring about 45°, and 

 anterior end gently arched; width of frontal lobe equal to about one and a half 

 times the whole length of the glabella. Three pairs of lateral glabellar furrows 

 present ; anterior pair situated near base of expanded anterior portion of 

 glabella, rather long, obliquely directed backwards, widening and deepening 

 outwards but not reaching axial furrows. Second pair situated at front end of 

 neck, and consisting of two isolated elongated deep pits or short grooves, 

 connected by faint longitudinal furrows with the inner ends of the first pair of 

 furrows. Third pair of furrows similar iu character to second pair, and situated 

 halfway down the neck. Axial furrows distinct, strongly curved outwards in 

 front of neck, nearly parallel along its sides. Occipital furrow strong, arched 

 forward in middle. Occipital ring rounded, widest in middle, and furnished with 



1 Walcott, " Palseont. Eureka District," 'Mon. U.S. Geol. Surv.,' vol. viii (1884), p. 61, pi. i.\, fig. 23. 



2 Walcott, ibid., p. 93, pi. xii, fig. 9. 



3 Schmidt, 'Rev. Ostbalt. Silur. Trilob.,' pi. 4, p. 60. pi. iv, figs. 46, 49. 



