106 • BRITISH PALAEOZOIC PHYLLOCARIDA. 



and has a nuchal slope of 60° ; difference of pressure has probably caused this 

 discrepancy. 



PI. XV, fig. 15, two valves, almost perfect ; measurements, | , 19 mm., 

 — , 13 mm.; A, 10 mm. at 40°; ,_,, 15 mm.; I, 8 (?) mm.; V, 100°. The two 

 valves very broadly and bluntly sagittate ; carapace circular. 



In dark-grey shale, weathering brownish. Valves rusty impressions. Con- 

 centrics nearly obliterated, but apparently were numerous and irregular in width. 

 Mus. Geol. Surv. Scotland. Marked 1/13/4/92. 



PL XV, fig. 16, two valves, similar to but larger than fig. 15, and more 

 distorted by pressure. | , 26 mm.; — , 17 mm.; A, 12 mm at 30°; ^_,, 

 17 (?) mm.; I, 8 (?) mm. ; V, 120°. Valves and carapace as in fig. 15 (allowing 

 for distortion). In thin, grey, mottled ashbed (?), finely micaceous, weathering 

 reddish. Valves rusty impressions ; concentrics numerous and irregular ; outer 

 rim present in places. 



From the Riccarton beds, Yad's Linn, near Hawick. Coll. Lapworth. British 

 Museum. No. 59621. 



PI. XV, fig. 12, may possibly be a fragment of a small A. Wilsoni. It consists 

 of the imperfect anterior portions of two valves, with concentric lines, distinct, 

 numerous, and irregular. Measurements : | , 10 (?) mm. ; — , 8 mm. ; A, 7 mm. 

 at 40°; ,_,, 11 mm. ; I, 5 (?) mm. ; V, 100°. 



In a hard, grey, micaceous shale. Longside Burn, Shankend, Roxburghshire. 

 Mus. Geol. Surv. Scotland. M 902 c. 



7. Aptychopsis Lapwoethi, if. Woodward, 1872. Plate XV, figs. 3, 7—10, 22. 



Abttchopsis peima, Barrande (part). Syst. Sil. Boheme, vol. i, SuppL, 1872, 



p. 457, pi. xxxiii, fig. 17 only. 



— Lapwoethi, H. W. Geol. Mag., 1872, p. 354. 



— — — Eeport Brit. Assoc, for 1872 (1873), p. 323. 



— — — Catal. Brit. Toss. Crust., 1877, p. 70. 



— — Lapworth. Quart. Journ. Geol. Soc, vol. xxxiv, 1878. 



p. 331 (in list). 



— — T.E. J. and H. W. Geol. Mag., 1884, p. 354. 



— — — Eeport Brit. Assoc, for 1884 



(1885), p. 90. 



— — Etheridge. Brit. Foss., vol. i, Palaeoz., p. 41. 



_ _ Woods. Catal. Type Foss. Cambridge, 1891, p. 133. 



This Phyllopod shield was briefly described by Dr. H. Woodward in his Report 

 on Fossil Crustacea, Brit. Assoc, for 1872. It is oval in shape, longer in the 

 fore and aft direction than in the transverse diameter. Concentric strise are 



