78 BRITISH SILURIAN BRACHIOPODA. 
Famity—CRANIAD/. 
Genus—Crantia, Retzius, 1781. 
Ref. Davidson, ‘ British Foss. Brach.,’ vol. i, Introduction, p. 122; and vol. ii, ‘ British 
Carb. Brach.,’ p. 192. 
Crania DivaRicata, A/‘Coy, sp. Pl. VIII, figs. 7—12. 
CRANIA ANTIQUISSIMA (?), MW‘Coy. Not of Eichwald. Synopsis of the Silurian Fossils 
of Ireland, p. 25, 1846. 
PsBUDO-CRANIA Divartcata, M‘Coy. Ann. Nat. Hist., 2nd ser., vol. viii, p. 388, 
1851; and Brit. Pal. Foss., p. 187, pl. i, u, figs. 
1,2, 1852; 
CRANIA — Dav. Monogr., vol. i, Introd. p. 122, pl. ix, figs. 
246, 247, 1853. 
=e CATENULATA (Salter, MS.), Baily. Data and Descriptions to accom- 
pany Quarter-sheet 35 N.E. of the Map of the Geolog. 
Survey of Ireland, p. 9, fig. 3, 1858. 
— pivaRicaTa, Salter, Siluria, 2nd ed., p. 212, fig. 2, 1859. 
Spec. Char.—Shell unattached ; usually longitudinally oblong-oval, sometimes slightly 
transversely so, or as wide as long, rather narrowed posteriorly, widest anteriorly. Poste- 
rior margin slightly indented. Valves flattened or very gently convex, and ornamented 
with numerous narrow, sharp, slightly prominent, radiating ribs or raised strize, increasing 
in number by the interpolation between the principal ribs of additional nblets, which 
commencing at variable distances from the posterior margin, extend to the front; 
a few concentric lines of growth traverse the surface of the valves. Three examples 
measured— 
Length 6, width 7 lines 
COR) HEE, 
eee SU, ee “alles a 
Obs.—The interior of the dorsal valve presents a wide broad margin indented poste- 
riorly (fig. 11, m). The divaricator oval scars (R), which lie close to the inner edge of 
the posterior portion of the flattened margin, are not very strongly indented, and present 
but small elevations on the cast ; towards the middle of the shell, or rather nearer to the 
posterior than anterior margin, may be seen two obliquely placed, ovate, muscular impres- 
sions, slightly concave in the shell (projecting in the cast) and separated from each other 
near their base by a space about equalling one of their width. These impressions are sur- 
rounded by a narrow ridge, and are (as supposed by Mr. Hancock) referable to the occlusor 
