APTYCHOPSIS SALTERI. 



109 



has had a strong rim, which is partly preserved. From Stennies Water, six and a 

 half miles north-west of Langholm, Dumfriesshire. Mus. Geol. Survey, Scotland. 

 M, 462 c. 



PI. XV, fig. 5, retains one perfect and one imperfect valve; the notch is 

 empty. It measures : | , 17 mm. ; — , 10 mm. ; _/ , 7 mm. at 45° ; ^_,, 9 mm. ; 

 I, 6 (?) mm.; V, 90°. Proportion, width to length as 20 to 23. In buffish- 

 coloured, hard, micaceous shale (like that of fig. 4) ; valves, rusty impressions ; 

 the outer rim is partly preserved. Stennies Water, Dumfriesshire. Mus. Geol. 

 Survey, Scotland. M, 466 o. 



9. Apttohopsis Salteri, E. Woodward, 1882. Plate XVII, fig. 6 ; and Woodcut, 



Fig. 8. 



Apttchopsis Salteei, H. Woodward. Geol. Mag., 1882, p. 389, pi. ix, fig. 17. 



— — T. B. J. and R. W. Geol. Mag., 1884, p. 355. 



— — — Eeport Brit. Assoc, for 1884 (1885), 



p. 91. 



This distinctly marked species had a suboval outline when perfect. The surface 

 is finely striate and rather undulate concentrically, and the outer border seems to 

 have had the edge bent downwards. 



This carapace differs from A. glabra ( PI. XV, fig. 11) and A. Wilsoni (figs. 15 



Fig. 9.— Fio. 10.— 



A. ovata. A. prima. 



All three of natural size and restored as to outline. 



Fig. 8. — Aptychopsis 

 Salteri. 



In A. Salteri the width is to length as 26 to 33 mm. ; A. ovata, 18 to 33 mm. ; A. prima, 18 to 21 mm. ; var. 

 secunda, 19 to 19 mm., Barrande's fig. 14 ; and A. glabra, 16 to 17 mm. 



and 16) in being oval and not circular, and the upper angle of the valve is more 

 acute than in A. Wilsoni. 



Measurements : | , 25 mm. ; — , 13 mm. ; _y , 10 mm. at 45° ; ,_,, 14 mm. ; 

 I, 10 (?) mm ; V, 90°. Proportion : width to length as 26 to 35. It is larger and 

 more oval than A. ovata, PL XV, figs. 4 and 5. 



■ In hard black shale. Upper Silurian (Wenlock Shale) ; Pencarreg, Caermar- 

 thenshire, South Wales. GoU. J. B. Lee. Brit. Museum. I, 1150. 



