136 BRITISH PALAZOZOIC FOSSILS. [Crusracra, 
Position and Locality.—Gaer Fawr (in the fine sandy beds), Montgomeryshire ; Cowan Head, and 
Underbarrow, Kendal, Westmoreland; in the Ludlow schists of Llanfair, Welchpool. 
A remarkable variety of the above, or perhaps a new species, much elevated, and the middle lobe 
forming a very long vertical ridge extending nearly to the dorsal sulcus, and not defined by a sulcus at the 
upper end, occurs in the schist at Dermydd Fawr, near Craig Bronbanog, N.W. of Corwen. 
Explanation of Figures.—PI. 1. E. fig. 2. Left valve magnified eight diameters, and natural size. 
BEYRICHIA COMPLICATA (Sa/t.) Pl. 1. E. fig. 3. 
ef —Mem. Geol. Surv. t. 8. f. 16. 
Sp. Ch.—Rotundato-quadrate, ends unequal, about one-third longer than deep, thickened border strongly 
defined ; sides flattened, divided by three very deep and wide sulci, extending obliquely from the ventral 
towards the dorsal margin, two of these almost reaching the dorsal margin and dividing the surface into 
three unequal lobes; that near the middle of the shell narrowest, that of the small end pyriform and larger, 
that at the large end largest, the latter again divided by the third suleus (which is much shorter than 
the others) into a small branch-like lobe from its inner side; the ventral ends of all these lobes occasionally 
swell into tubercles. Length about one line. 
The figure of the Survey is incorrect in regard to the proportion of size between the lobe of the 
larger end and the branch which originates from it. 
Position and Locality—Very abundant in the calcareous flags of Pont y Meibion, two miles S. of 
Llansantfraid on the Ceiriog; Milltit Cerrig, Llangynnog; Cwm of the Cymerig, Bala, Merionethshire ; 
Hill N. of Moel Uchlas; Pen y Park, Llanfyllin; Mathyrafal, S. of Meifod, Montgomeryshire; Tre Gil, 
S. of Llandeilo. 
Explanation of Figures —PI. 1. E. fig. 3. Left valve magnified eight diameters, and natural size, from 
the schists of Pont y Meibion.—Fig. 3a. Right valve magnified eight diameters, and natural size. 
BEYRICHIA STRANGULATA (Sa/t. in App.) PI. 1. E. fig. 1. 
Sp. Ch.—Oblong, ends nearly equal, depth varying from half to two-thirds the length; dorsal margin 
slightly flattened, ventral margin straight, ends rounded; thickened margin tumid and separated from the 
sides by a very deep sulcus; sides moderately convex, with a small, oval, nearly vertical depression, a little 
nearer the narrow end than the other, and having a small tubercle on its margin nearest the narrow end. 
Length about one line. 
The sulcus which defines the thickened margin is so very deep in this species, that in many specimens 
portions break easily off from the sides, and appear at first sight to have been deficient: this has obviously 
misled Mr Salter in his view of the species, which, however, as above defined, is a very good one; he informs 
me that his Cytherina levigata (Quart. Geol. Journ. Vol. I. p. 445), is the same species. Sometimes the 
depression is less elongated than usual, being elliptical, and not reaching the margin. 
Position and Locality—In great abundance in the calcareous schists at Coniston Water-Head, 
Lancashire. 
Explanation of Figures.—P\. 1. K. fig. 1. Left valve of deep variety, magnified eight diameters, and natural 
size from Coniston.—Fig. la. Right valve of long variety, magnified eight diameters, Coniston.—Fig. 1 6. 
Left valve of intermediate variety, and natural size; the thickened margin imperfect in parts, the dotted line 
indicating its completion. From Coniston. 
Genus. CERATIOCARIS (M°Coy). 
Ref—M Coy, Ann. Nat. Hist. 2nd Series, Vol. IV. p. 412. 
Etym.—Keparwv, a pea-pod, and Kapis, a shrimp. 
Gen. Char.—Carapace bivalve, the dorsal line simply angulated (? undivided), with a slight furrow beneath 
it on each side; sides semielliptical, much elongated from before backwards, evenly convex; ventral margin 
