a ee we 
- 
ORTHIDA. 245 
(p. 28, pl. iv, fig. 8), “bears also much resemblance to certain varieties of O. 
calligramma. 
Position and Locality. his remarkable species seems to have had a very extended 
vertical as well as geographical range, for we find it in the Llandeilo, Caradoc, Llandovery, 
and Wenlock formations. 
In the Llandeilo it occurs at the west of Stiper Stones; at Tan-y-Craig, Builth ; one 
mile north-west of Llanerchymedd ; Treiorwerth; Tyn-twr, four miles south of Llangefni 
(Salter), &c. 
In the Caradoc, at Moelydd, near Oswestry; Carneddan, Builth; Bettws-y-Coed ; 
Dolwyddelan ; Yspytty Evan, Caernarvonshire; south of Llangollen ; south-east of Cerrig- 
y-Druidion, Denbighshire ; Llanfyllin; Meifod; Llanwyddyn; Welshpool, Montgomery- 
shire ; and east of Bala Lake (Salter). Hithen Ridge, east of Berwyn Hills ; at Horderley, 
Glyn Ceriog, and in several localities, such as at Helm Gill Dent, in the Coniston Lime- 
stone of the Lake district, &c. 
In the Llandovery at Huntley Hill, May Hill, Presteign ; Longwind ; Chirbury, &c. 
. For its occurrence in the Woolhope and Wenlock Limestones localities have been already 
given, 
In Scotland it occurs in several places near Girvan, in Ayrshire. 
Iu Ireland it has been found in many localities, as Desertcreat, Tyrone, Grangegeeth, 
&c., County Meath ; Knock-Mahon, Tramore, County Waterford, &c. 
Abroad it has been found in Russia, Sweden, America, &c., and Mr. Billings 
mentions the var. Davidsoni as being abundant at the Jumpers and in other localities in 
the Island of Anticosti. 
OrtHis puicata, J. de C. Sow. (sp.). Pl. XXXV, figs. 25, 26; and Pl. XXXVII, 
fie. V- 
Sprrirer ? piricatus, J. de C. Sow. Sil. Syst., pl. xxi, fig. 6, 1839. 
OrTHIS CALLIGRAMMA, var. PLIcATA, Salter. Mem. Geol. Survey, p. 376, 1848. 
— puicata, M‘Coy. Brit. Pal. Foss., p. 222, 1852. 
—  CALLIGRAMMA, var. pLIcATA. Salter. Siluria, 2nd ed., pl. v, fig. 7, 1859; and 
Mem. Geol. Survey, vol. iii, p. 336, pl. xxii, 
fig. 5, 1866. 
Spec. Char. Semicircular or sub-quadrate ; hinge-line straight, exceeding the width 
of the shell ; cardinal extremities forming slightly mucronate wings; lateral and frontal 
margins rounded, Ventral valve evenly and moderately convex; beak not projecting ; 
area triangular, flat, at times large ; fissure narrow. Dorsal valve less deep or convex 
than the opposite one; area narrow. Surface of both valves marked with from forty to 
