190 BRITISH SILURIAN BRACHIOPODA. 
fold being scarcely defined. From not having been able to obtain an insight into the 
interior of this and the preceding species, it is not possible to feel quite certain that they 
really belong to the genus RAynchonella. 
Position and Locality. Rh. Portlockiana occurs in the Caradoc at the Chair of Kildare, 
in Ireland. Specimens may be seen in the Museum in Jermyn Street. 
RuYNCHONELLA ? Epgeniiana, sp.nov. Pl. XXIV, figs. 27—28. 
Spec. Char. Transversely oval, valves moderately convex. Dorsal valve divided into 
three almost equal parts, of which the central one forms the mesial fold. Ventral valve 
convex, with a deep concave mesial fold. Surface smooth. 
Length 5, width 6 lines. 
Obs. Of this species (?) Mr. Wyatt-Hdgell found two incomplete specimens or valves 
only; and consequently, from such scanty material, it is not possible to offer a com- 
plete or satisfactory description. I am likewise very uncertain with reference to the genus 
to which it should be referred, but have provisionally left it with hynchonella. It might 
perhaps belong to Mervstella? 1 have, however, considered it desirable to describe and 
figure the shell as far as practicable, on account of its having been obtained from rocks of 
the Llandeilo age, near Ffairfack. The specimens are in the late Mr. Wyatt-Edgell’s col- 
lection. 
RHYNCHONELLA ? NAVICULA, Sow. (sp.) Pl. XXII, figs. 20—23. 
TBREBRATULA NavicuLA, J. de C. Sow. Silurian System, pl. v, fig. 17, 1839. 
ATRYPA — M‘Coy. A Synopsis of the Silurian Fossils of Ireland, 
p. 40, 1846. 
THREBRATULA — Barrande. Silurische Brachiopoden aus Bohmen, pl. xv, 
fig. 4, 1847. 
— — Dav. Bull. Soc. Géol. de France, 2nd series, vol. v, 
p. 328, 1848. 
Hypornyris — Phillips. Memoirs of the Geol. Survey of Great Britain, 
p. 281, 1848. 
ATRYPA — D’Orbigny. Prodrome, vol. i, p. 40, 1849. 
Hemituyris — M‘Coy. Brit. Pal. Foss., p. 204, 1852. 
RHYNCHONELLA — Salter. Siluria, 2nd ed., p. 545, pl. xxii, fig. 12, 1859. 
— ?— Lindstrém. Gotlands Brachiopoder, p. 381, 1860. 
— — Salter. Memoirs of the Geological Survey of Great Britain 
vol. ill, p. 279, 1866. 
Spec. Char. Shell rather small, ovate or boat-shaped, widest and most rounded pos- 
teriorly, gradually narrowing anteriorly, slightly convex in front. Ventral valve very 
convex and arched, obscurely keeled along the middle, the lateral margins forming a 
