1869. ] DAVIDSON—-PEBBLE-BED BRACHIOPODA. 83 
rous thread-like striz, which increase in number by the interpolation 
of one or two smaller striz between each pair of the principal. 
Dimensions variable. Length 5, width 6, depth 2 lines. 
Although this shell was identified by Mr. Salter with Orthis redux 
(Barrande), both M. de Verneuil and myself entertain misgivings as 
to the correctness of the identification. The Bohemian Silurian 
species is not well known; the internal cast only has been figured 
by Barrande. It is a larger shell, and the median sinus is much 
deeper than what we find in our Budleigh examples. At any rate 
we have given to it the varietal designation of Budleighensis, which 
name can be hereafter retained as a specific one should the two 
shells be found to be specifically distinct. The correct identification 
of this species becomes very important, since no less than seven 
other forms have been found in the same pebbles with it. We 
therefore cannot determine at present whether it and its accompany- 
ing forms are of Silurian or of Devonian age. 
24. Orruis Berrnorsr, Rouault?, var. erratica, Dav. Pl. V. figs. 
13-16. 
Day. Sil. Mon. p. 238, pl. xxxii. figs. 21-28, 
This species has been fully described and illustrated at p. 233 of 
my Silurian Monograph. I cannot say whether it agrees with the 
Orthis Berthoisi, Rouault, as I have never seen the French type; 
nor can I say whether Mr. Sharpe was correct in identifying his 
Portuguese examples with Rouault’s species. Budleigh specimens 
seem to resemble the Portuguese shell, while differing in some minor 
details ; I have provisionally applied to them the varietal designation 
of erratica. Mr. Sharpe states that he obtained the fossil he iden- 
tifies with O. Berthois: from the lowest division of the Silurian 
system, at Portela de Loredo, in Portugal. 
25. OrtHis Vatpyana, Day. PI. V. figs. 23-25. 
Sil. Mon, p. 235, pl. xxxii. figs. 29-33. 
A description of this shell will be found in my Silurian Mono- 
graph. Mr. Vicary informs me that he believes that he has found it 
associated with O. Vicaryi in the same pebble. It appears also to 
bear some resemblance to O. Gervillei (Defr. & Barr.); but there is 
sufficient difference between the two forms to consider them specifi- 
cally distinct. 
26. Orruis putvinaTA, Salter. Pl. Y. figs. 17-19. 
Quart. Journ. Geol. Soc. vol. xx. p. 294, fig. 8, 1860. 
? Porambonites, Salter, ibed. p. 295, pl. xvii. figs. 10-12. 
Transversely oval; hinge-line shorter than the width of the shell; 
valves uniformly and moderately convex, surface marked by fine 
radiating lines or raised striz, increasing in number towards the 
margin by the interpolation of shorter strie. Area narrow. The in- 
ternal cast of the ventral valve shows a large saucer-shaped muscular 
depression, divided in the middle by a widish convex ridge or space ; 
in the internal cast of the dorsal valve there is a small oval slit, 
2 : 
