some British Fossil Crustacea. 4.07 
ments, tnree similar ones belong to the pygidium, the termi- 
nal one being obtusely trigonal ; the side lobes are flattened, 
and more than double the width of the axal lobe ; pleure nearly 
straight, narrow, and for the greater part of their length flat- 
tened, and having a broad, nearly mesial pleural sulcus deeply 
punctured like the cheeks, dividing each into two parts, the 
posterior largest and forming a thick, smooth, rounded ridge, 
bent down and a little backwards in the distal third of its 
length, swelling to a thick narrow ridge in the middle, the 
sides and extremity expanding into a broad, thin, foliaceous 
appendage; the pygidium terminates in six broad ovate, leaf- 
hike, semimembranous flaps. Length of thorax and pygidium 
2 inches 2 lines, width 2 inches 3 lines, width of axal lobe 
6 lines. 
This magnificent Trilobite can only be confounded with the 
Eecoptochile clavigera (Beyrich sp.), from which it is distin- 
guished by the much greater width of the lateral lobes of the 
thorax, and the thin, flat, leaf-like appendages of the pygidium, 
which in that species resemble thick pear-shaped clubs. A com- 
parison with the old description and casts published by Green 
induces me to place this Trilobite in his little-known genus 
Cryphaus, and to doubt very much the propriety of separating 
Eccoptochile of Hawle and Corda from it, the only difference 
being the thickness of the marginal appendage in the Bohemian 
genus. 
The nearly entire specimen described was collected by Prof. 
Sedgwick from the Wenlock shale two miles north of Builth. 
(Col. University of Cambridge.) 
Ceraurus octo-lobatus (M‘Coy). 
Sp. Char. Pygidium transversely elliptical, twice as wide as long, 
two first rmgs of the axis narrow, distinct, third or terminal 
one large, terminating in four flattened elliptically pointed 
lobes; two rather larger similar lobes on each side. Length 
21 lines. 
This curious little species differs from all of this and the allied 
genera in having the terminal segment of the pygidium quadri- 
lobate, so that the margin of the pygidium exhibits eight mar- 
ginal pointed lobes in all. 
It is figured in the ‘ Memoirs of the Geol. Survey’ from Sholes 
Hook, under the same reference as the cephalic shields there called 
Spherexochus juvenis (Salter)*, but not alluded to in the text. 
In the limestone of Rhiwlas. 
(Col. University of Cambridge.) 
* Corrected to S. clavifrons (Dal.) in the list of plates prefixed to the 
same work. 
