﻿PLATE XVIII. 



DEVONIAN SPECIES. 



Fig. 



1 . Streptorhynchus umbraculum, Schloth. = 0. crenisiria, Sow. From the figure in the 



' Trans. Geol. Soc./ vol. v, pi. xxxvii. Fig. 7, Middle 

 Devonian, Plymouth. 



2. „ „ Phillips' figure, 'Pal. Foss. of Devon,' &c, pi. xxvii, fig.113. 



3. „ „ Internal cast of the ventral valve. 



4. crenistria, Phillips' P. arachnoidea. Impression from the Upper 



Devonian, Brown Grits of Braunton. 



5. umbraculum. Middle Devonian, Woolborough. More lines should 



have been drawn between the ribs in the enlarged 

 shell fragment, fig. 5 B . 



0. ? „ From Woolborough. I am uncertain about the species 



to which this valve belongs. 



7 — 9. ,, crenistria. These figures are taken from Phillips (' Pal. Foss. 



Devon,' &c, pi. xxvi, fig. 112), and referred erro- 

 neously to Orthis compressa, Sow., ' Sil. Syst.' Fig. 8 

 belongs to Chonetes Hardrensis. Fig. 7 to Strep t. 

 crenistria. Upper Devonian, Croyde. 



10. „ ? semicircularis, Phillips. This is a very doubtful so-termed species. The 



figure is copied from that given by Phillips in his 

 ' Pal. Foss.,' pi. lviii, fig. 112\ Upper Devonian, 

 Pilton. 



11. „ crenistria, (Orthis calcar). From Phillips' figure, c Pal. Foss./ pi. lviii, 



fig. 112. Upper Devonian, Pilton. 



12. „ „ (? "Orthis plicata, Sow.) From the original internal cast, 



' Geol. Trans.,' vol. v, pi. liii, fig. 10. Upper Devonian. 

 13,14. Leptana ? Looiensis, Dav. Casts from the Grits of Looe, in Cornwall. Collection 



of Mr. Pengelly. 



15 — 18. „ interstrialis (Orthis), Phillips. Figs. 15, 16, 17, Middle Devonian, 



Barton. Collection of Mr. Lee. Fig. 18, Collection of 

 Mr. Stewart. 



19 — 21. „ ? nobilis, M'Coy. Figs. 19, 20, ventral valve, Woolborough Quarry. 



Collection of Mr. Pengelly. Fig. 21, id., in British Mu- 

 seum : a, ventral valve ; b, internal surface of dorsal valve. 



