28 BRITISH CAMBRIAN TRILOBITES. 



Type. — Specimen 5849 !• in the British Museum (Natural History) belonging- to 

 the Belt collection, probably includes some of Belt's original types. 



Horizon and Localities. — Upper Lingula Flags: White-leaved Oak, Malvern; 

 Dolgelly. 



24. Agnostus obtusus, Belt. Plate Tl, fig. 2:5. 



1868. Agnostus oltusus, Belt, Geol. Mag., vol. v, p. 10, pi. ii, figs. 15, IT. (heads only). 



Head quadrate, with a wide margin. Glabella bilobed ; the anterior lobe 

 quadrate and but faintly separated from the posterior lobe; posterior lobe nearly 

 parallel-sided, with a prominent central tubercle near its front margin ; basal lobes 

 large and triangular, meeting behind the posterior lobe. Cheeks nearly uniform 

 in width throughout, confluent in front of the glabella. 



Head about 3 mm. long and 3 — 3*5 mm. wide. 



Under the description of A. cyclopyge I have given reasons for referring to 

 that species the tail which Belt ascribed to this head. If this view be correct, the 

 tail of A. obtusus is still unknown. The species, however, probably belongs to the 

 section Limbati. 



Type. — Probably specimen 58494 in the British Museum (Natural History). 



Horizon and Locality. — Upper Lingula Flags: Dolgelly. 



Section Parvifeontes. 



25. Agnostus truncatus, Brogger. Plate II, fig. 24. 



137. r >. Agnostus, n. sp., Brogger, Geol. For. Stockh. Fort., vol. ii, pi. xxv, fi> 1. 



1879. Agnostus truncatus, Brogger, Nvt Mag. for Naturv., vol. xxiv, p. 72, pi. vi, fio-. 8. 



1896. Agnostus parvifrons, var. truncatus, G. F. Matthew, Trans. N. Y. Acad. Sci., vol. xv, p. 222. 



Head rounded in outline, gently convex, with narrow margin. Glabella, which 

 seems to represent only the posterior and basal lobes, short, barely half the total 

 length of the head, bounded by nearly parallel lateral furrows, and by a straight 

 transverse furrow in front; basal lobes small. 



Thorax : axis with a lateral nodule on each side ; pleurae grooved. 



Tail semi-elliptical, with narrow margin. Axis fairly wide, somewhat con- 

 stricted about one quarter of its length from the front; anterior segment com- 

 pletely defined by a shallow furrow and very short; second and third segments 

 not distinctly separated, with an elongated tubercle extending through what appears 



