112 TRILOBITES OF GIRVAN. 



Genus ACIDASPIS, Murchison. 

 1. Acidaspis barrandei, Fletcher and Salter, 1853. Plate XV, fig. 11. 



1848. Acidaspis bispinosus, Salter, e. p. Mem. Geol. Surv., vol. ii, pt. i, pi. ix, fig. 4 only. 



1853. Acidaspis barrandii, Fletcher (dixit Salter), Mem. Geol. Surv., dec. vii, p. 6, pi. vi. 



1854. Acidaspis barrandii, Morris, Cat. Brit. Foss, 2nd ed., p. 98. 



1859. Acidaspis barrandii, Murchison, Siluria, 3rd ed., p. 261, foss. 64, fig. 9. 



1890. Ceratocephala barrandei, Clarke, 44th Rep. New York State Museum, p. 93. 



1896. Acidaspis barrandei, Lake, Quart. Journ. Geol. Soc, vol. lii, p. 241, pi. viii, figs. 1—3. 



Remarks.— One fine head-shield with the two pairs of posterior spines well 

 preserved, and another less perfect one, both from Penkill, represent this species 

 in Mrs. Gray's collection. Mr. Lake's full and recent description (op. cit.) renders 

 further remarks needless. Clarke (op. cit.) is desirous of substituting Warder's * 

 earlier name Ceratocephala for the whole genus usually termed Acidaspis, and of 

 using it in a stricter sense to designate a subdivision of the genus. But the name 

 is usually rejected because the name Ceratocephalus had been previously applied by 

 De Candolle to a genus of plants. 



Collection. — Mrs. Gray. 



Horizon and Locality. — Penkill Group (Tarannon = part of Mrs. Gray's U. 

 Llandovery) : Penkill. 



Acidaspis callipareos, Wyville Thomson, 1857. Plate XV, figs. 12, 13. 



1857. Acidaspis callipareos, Wyville Thomson, Quart. Journ. Geol. Soc, vol. xiii, p. 208, pi. vi, 



figs. 11, 12. 



? 1857. Acidaspis hystrix, Wyville Thomson (e. p.), ibid., pi. vi, figs. 7, 8 (won figs. 6, 9, 10). 



1876. Acidaspis callipareos, Armstrong and Young, Cat. West. Scot. Foss., p. 15. 



1877. Acidaspis callipareos. Woodward, Cat. Brit. Foss. Crust., p. 18. 



1878. Acidaspis callipareos, Nicholson and Etheridge, Mon. Silur. Foss. Girvan, fasc. i, p. 125. 

 1896. Acidaspis callipareos, Lake, Quart. Journ. Geol. Soc, vol. lii, p. 243. 



Remarks. — The typical locality for this species is Mulloch Hill. It was founded on 

 a head-shield, but it is probable that the thorax described and figured by Wyville 

 Thomson from Rough Neuk, Mulloch Hill, as belonging to A. hystrix, really should 

 be attributed to A. callipareos, for A. hystrix typically comes from the Balclatchie 

 (Llandeilo) beds. Nicholson and Etheridge (op. cit.) were also inclined to hold 

 this view. In Mrs. Gray's collection two imperfect head-shields, one with a few 

 body-rings attached, from Woodland Point, appear to be attributable to this 

 species, and perhaps a body-ring from Newlands also belongs to it. 



1 Warder, ' Amer. Journ. Sci.,' vol. xxxiv (1838), p. 377. 



