A) BRITISH SILURIAN BRACHIOPODA. 
Linevta Rovautti, Salter. PI. I, figs. 14—20. 
Quarterly Journal Geol. Soc., vol. xx, pl. xvii, figs. 4, 5, 1863. 
Spec. Char. Shell thick, triangular, longer than wide ; front either straight or slightly 
convex ; sides gently arched and converging, so as to produce in the larger valve a taper- 
ing pointed beak ; dorsal valve a little shorter than the opposite one, uniformly and highly 
convex ; the ventral not so deep as the dorsal valve, and flattened along the middle ; 
beak of the ventral valve produced about two lines beyond that of the dorsal valve. 
External surface marked by numerous more or less strongly indented concentric lines of 
growth. ‘Two specimens measured— 
Length 23, width 17 lines. 
by ust Oh. fod 2 Gi-c65: depth 9! lines. 
Obs. This curious species appears to be not uncommon in the Lower Silurian 
“ Armorican Grit,” or quartzite boulders at Budleigh Salterton, in Devonshire, and is also 
now and then found with its two valves united. All the specimens I have seen were 
longer than wide, while Z. Brimonti is stated by M. Rouault to have been wider than 
Jong ; and it would appear that both it and the species under description were thick, robust, 
and remarkably convex shells, more so, indeed, than is usual with the generality of species 
of the genus. We have also the interior (although not perfectly preserved) of the dorsal 
valve, which shows that its muscular scars agreed in shape, as well as in position, with 
those observable in other species of Lingula; while strong radiating strize are also visible 
on the internal cast. This species was well described and figured by Mr. Salter. It 
approaches somewhat in shape to Z. erwmena, Phillips; but of the last-named shell we 
have not hitherto obtained bivalved examples, and, consequently, cannot say whether it 
was as convex as Z. Rouaulti. Mr. Salter considers the two to be perfectly distinct. 
Lineuia crumeNA, Phillips. PI. II, figs. 1—6. 
LINGULA cRUMENA, Phillips. Memoirs of the Geological Survey of Great Britain, 
vol. 11, part i, p. 369, pl. xxiv, 1848. 
— — Murchison. Siluria, p. 74, fig. 5, 1859. 
Spec. Char. More or less triangular or cuneiform, widest anteriorly ; sides either 
regularly and very slightly convex from close to the front to the extremity of the pointed 
beak, or the convex sides form an inward curve at about their middle ; beak acuminated 
and acutely pointed; front gently convex, sometimes nearly straight; ventral valves 
moderately convex, but in some instances flattened along the middle, and marked by more 
or less strongly indented lines of growth. 
