PLAGIOLOPHUS. 19 



This is the only known species of the genus, and I have the pleasure of dedicating it 

 to my friend Mr. Bowerbank, to whom I am indebted for having, with his accustomed 

 liberality, placed the whole of his fine collection of these fossils at my disposal. 



Genus — Plagiolophus, Bell. 



Char. Gen. Testa transversa, ovata, regionibus distinctis, fronte prominente. 

 Oculi subdistantes. Orbita supra bifissse, usque ad medium regionis hepaticse extendentes. 

 Antenna externa inmimse, articulo basali hiatum orbitse claudente ; interna articulo basali 

 triangulo, gibbo. Pedipalpi externi longitudinaliter bi-sulcati. Pedes antici mediocres, 

 manu triquetra, digitis elongatis, digito immobili tuberculo armato, altero inermi. Abdomen 

 maris articulis a tertio ad quintum unitis; fcemin^e ? 



Species unica. Plagiolophus Wetherelli, mild. Plate II, figs. 7 — 13. 



Bescr. Carapace about one fifth or one sixth broader than long, widest at about one 

 third from the front ; latero-anterior margin very short, with five processes, of which the 

 orbital is inconspicuous, the first hepatic very small, the second hepatic a little larger, 

 flattened and triangular ; the epibranchial the largest of all, conical ; and the mesobranchial 

 of similar form to this, but much less prominent and more distant from the former than 

 any of the others ; front somewhat projecting, rounded, with a longitudinal groove ; 

 the regions of the carapace and their lobes very distinct, each with a considerable 

 elevation, which is strongly and closely granulated, the intervening furrows broad and 

 perfectly smooth ; gastric region of the usual size and form in the Canceridae ; the epigastric 

 lobes small, but conspicuous, and close to the front j the protogastric rounded and very 

 broad, and separated from each other by an elongated process of the mesogastric, which 

 reaches nearly to the front ; the mesogastric distinguished from the metagastric only by a 

 slight notch on each side ; cardiac region with a transverse ridge ; hepatic region rather 

 large, gibbous in the centre ; branchial regions with two transverse elevations, the first 

 across the epibranchial lobe, curved downwards towards the cardiac region, the second 

 across the metabranchial, and forming, with the raised band of the epicardiac lobe, 

 a continuous ridge extending almost across the carapace ; mesobranchial lobe extremely 

 small ; posterior margin of the carapace with a raised border ; orbits opening directly 

 forwards, and extending outwards as far as the middle of the hepatic region ; the superior 

 ridge granulated, and with two fissures ; the antennal region is more or less mutilated in 

 all the specimens I have seen, but enough has remained to afford a probable conjecture as 

 to the direction and relations of the antennae ; the basal joint of the antennules is perfect 

 on each side in one specimen, and is of an elongate (transverse) triangular figure, and 



