ORDOVICIAN AND SILURIAN BRACHIOPODA OF THE GTRVAN DISTRICT. 825 



longitudinal lines. The surface of the shell appears to have been covered with rather 

 strong numerous rounded radii which project over the edge as minute marginal teeth, 

 but no pustules can be detected. Indeed, the whole character of the shell suggests 

 its relationship with Davidson's Crania Crofti* which Von Huene t places in "the 

 genus Philhedra ; but the marginally projecting radii especially resemble Pseudo- 

 crania pectinata, Gagel,} from the Jevesche Bed of Estland. 



Dimensions. — Length, 7'5 mm. ; width, 9'0 mm. ; height, c. 3'0 mm. 



Horizon. — Drummuck Group (Starfish Bed). 



Locality. — Thraive Glen. 



Genus Pholidops, Hall. 



Pholidops antiqua (Schlotheim) ? 



(Plate V, figs. 1-3.) 



1822. Patellites antiquus, Schlotheim, Petrefaktenkunde, Supply i, p. 62, t. xii, fig. 2. 

 1899. Pholidops antiqua, Von Huene, Verh. Russ. Miner. Gesell. St Petersburg, ser. 2, Bd. xxxvi, p. 270, 

 text-fig. 11, t. ii, figs. 19-21 (and references). 



A few badly preserved specimens of a species of Pholidops in Mrs Gray's collection 

 from Shalloch Mill appear to have the muscle-scars, scutellum, and pallial line 

 developed in the same manner as Ph. antiqua, Schloth., which they resemble rather 

 than the Silurian species Ph. implicata (i8ow.).§ But the material is too imperfect 

 for a precise determination. The same remarks apply to a specimen from the 

 Starfish Bed. 



Horizons. — (l) Whitehouse Group; (2) Drummuck Group (Starfish Bed). 



Localities.— (l) Shalloch Mill; (2) Thraive Glen. 



Pholidops implicata (Sowerby). 

 (Plate V, fig. 4.) 



1839. Patella 1 implicata Sowerby, in Murchison's Silur. Syst., p. 625, pi. xii, fig. 14a. 



1866. Crania implicata (Sowerby), Davidson, Mon. Brit. Foss. Brach., vol. iii, pt. vii, p. 80, pi. viii, 



figs. 13-18. 

 1883. Pholidops implicata (Sowerby), Davidson, op. cit., vol. v, Silur. Suppl., p. 216, pi. xvii, fig. 48. 



This interesting little species is represented on several horizons in the Llandovery 

 of Girvan, and Davidson recorded it from the Penkill and Woodland Point Beds. 

 The curious central scar, well described and illustrated by Von Huene, || is clearly 

 seen in several specimens. The relations of this species with Ph. antiqua (Schl.) are 

 discussed by Von Huene (op. cit., p. 281), and again by Moberg and Gronwall.H 



* Davidson, op. cit., vol. v, Silur. Suppl., p. 215, pi. xvii, figs. 54-56. + Von Huene, op. cit., p. 217. 



\ Gagel, Brach. camb. silur. Gesch., 1890, p. 25, t. i, fig. 11. 

 § Davidson, Mon. Brit. Foss. Brach., vol. iii, pt. vii, p. 86, pi. viii, figs. 13-18. 

 || Von Huene, op. cit., p. 276, t. ii, figs. 22-25 ; text-fig. 12. 



1 Moberg and Gronwall, " Om Fyledalens Gotlandium," Lunds Univ. Arsskrift, N.F., Af. 2, Bd. v, No. J, 1909, 

 p. 30, t. ii, figs. 8, 9. 



