﻿84 



BRITISH DEVONIAN BRACHIOPODA. 



Streptorhynchus ? persarmentosus, M" Coy (sp.). PI. XVI, fig. 5. 



Oimns persakmentosa, WCoxj. British Pal. Fossils, p 385, pi. ii A, fig. 9, 1852. 



Spec. Char. " Transversely oblong, hinge-line nearly as wide as the shell, ends 

 obtusely sub-truncated, slightly rounded; surface covered with thick rugged, rounded, 

 fiexuous, radiating ridges, about half their thickness apart ; about five in three lines in the 

 middle of the shell at six lines from the beak, branching four or five times between the 

 beaks and margin, counting about 130 at the margin of a large specimen : those towards 

 the sides straighter and finer than those in the middle. Average width three inches, 

 length probably one third of the width, but cannot be stated accurately, owing to the dis- 

 tortion of all the specimens. This, species very closely resembles 0. sarmentosa (M'Coy) 

 of the older rocks in form, and the peculiar twig-like mode of branching of the ribs on the 

 middle of the shell, and the straighter and finer ones of the sides ; but is distinguished by 

 the very much greater number of the ridges, as in the case of that species, the distortion 

 is usually such, that I can make no probable approximation of the proportional length. 

 The coarseness of the ridging separates the present species from the American Stroph. 

 nervosa and S. bifurcata (Hall) of the Chemung group." 



Position and Locality. Common in the Devonian shale of Polruan, Cornwall ; in the 

 reddish Devonian schists of East Looe ; and schists of Eowey. 



Oh. I have reproduced Prof. M'Coy's description, because, feeling exceedingly 

 uncertain as to the specific value of this so-termed species, of which I have not been able to 

 procure satisfactory material, I do not desire to express any opinion upon the subject 

 further than to say, that it appears to me to belong to Streptorhynchus and not to Orthis. 

 It is always most hazardous to propose new species on such imperfect, shortened, 

 and otherwise distorted specimens as those that have served for C. persarmentosa. 



Sub- yarns — Lept.en a, Batman. 



Lept/ena ? PI. XVIII, figs. 13, 14. 



Spec. Char. Transversely semicircular, hinge-line straight, nearly equal, or slightly 

 exceeding the width of the shell. Dorsal valve almost flat to within a short distance of 

 the front, when the valve becomes slightly curved or convex. External surface orna- 

 mented with from forty to fifty radiating angular ribs, but of which about one third are 

 due to bifurcation. Proportions variable. 



