BRITISH SILURIAN BRACHIOPODA. 161 



55. Rhynchonella ? Maccoyana, Bav. Dav., Sil. Mon., PI. XXV, figs. 17, 18, 19 



(not 16 or PI. XXVI, figs. 1—3); Sil. 

 Sup., PI. VIII, fig. 33. 



At p. 195 and in PI. XXV and PI. XXVI of my ' Silurian Monograph,' two distinct 

 species have, I beUeve, been described and figured under the name of Porambonites 

 iniercedens. Pander. The one, PL XXV, fig. 16, and PI. XXVI, figs. 1—3, may 

 perhaps be referable to the Russian genus and species, but the form from the Caradoc 

 Limestone of Wrae, in Peebleshire, PI. XXV, figs. 17, 18, 19, has all the appearance of 

 being a Bhynchonella. This was the feeling entertained by Mr. Salter and myself at the 

 time, and I did not hesitate to observe in p. 196 that we could not feel entirely satisfied 

 as to the correctness of the identification. It will therefore be necessary to describe 

 the Wrae species under a separate designation. 



Shell transversely subpentagonal, wider than long, greatest breadth about the middle, 

 sides convex ; dorsal valve more convex than the ventral one, fold broad, moderately 

 rounded and of small elevation ; ventral valve convex, with a wide, moderately-deepened 

 mesial sinus ; beak small, incurved ; surface smooth. 

 Length 13, breadth 17, depth 11 lines. 



In addition to the specimens which I have seen in the Woodwardian Museum, several 

 other examples from the Wrae Limestone have been lent to me out of the Museum of the 

 Geological Survey of Scotland. These were obtained from Glencotho Quarry, near 

 Broughton, in the same county, and bear a still more striking general resemblance to 

 some Carboniferous species of Rhynchonella such as to Bh. acuminata, var. platyloha. 



Some similar examples have been found by Mrs. R. Gray in the Middle Caradoc at 

 Shallock Mill, Girvan. 



Genus — Pentamerus, Soto, 1813. 



Some Swedish examples of Pentamerus {P. tenuissimastriata)^ Walmstedt, have 

 measured 5f inches in length by nearly 4 inches in breadth. British specimens of P. 

 Knightii have attained those proportions. 



56. Pentamerus oblongus, /. de C. Sow. Dav., Sil. Mon., PL XVIII, figs. 1 — 12 ; 



PL XIX, figs. 1, 2. 



This species has been fully described and illustrated at p. 151 of my 'Silurian Mono- 

 graph.' It seems, as far as I am aware, restricted to rocks of the Llandovery period. It 



