336 MR. T. BELL ON THE GENUS CANCER. 
was the common large eatable Crab of our coasts, the Cancer Pagurus, Linn. To this the 
name Platycarcinus was given by Latreille; an infelicitous appellation certainly, as 
none of the species are characterized by any particular degree of flatness of the body, 
and some of them even possess a rather remarkable degree of elevation. Dr. Edwards, 
with great correctness and tact, united to the genus, thus restricted in its characters, a 
second species, the Cancer irroratus of Say ; and to these I have the satisfaction of adding 
three entirely new and highly interesting species, collected by Mr. Cuming ; an acqui- 
sition which, whilst it increases our opportunities of fixing and appreciating the cha- 
racters of the genus, renders a complete revision of it necessary. It is, indeed, worthy 
of remark, that the specific character of Canc. Pagurus as given by Dr. Leach in his 
‘ Malacostraca Podophthalma Britanniz,’ is applicable, with very little latitude, to all 
the species now known, as they agree, without exception, in the margin, on each side, 
having nine, or more properly ten divisions (the last being obsolete), in the front being 
trifid, and the carapax granulated. 
The application of the name Cancer to the present genus renders it necessary to attach 
a new generic term to the group to which Dr. Edwards had appropriated it, and which 
he has characterized with his accustomed discrimination. It is very nearly allied to 
Carpilius, from which some of the species scarcely differ except in the form of the legs, 
which in Carpilius are round, and in the other group much flattened and fringed with 
hair. I propose for this genus the name Platypodia; and I conceive that in making 
these alterations in the nomenclature of this family, I am not intrenching on any of the 
acknowledged rules by which these matters are generally regulated, but rather, by so 
early an interference, contributing to their establishment. 
The genus Platypodia on the one hand approximates to Carpilius by Plat. rosea and 
Plat. interrupta, and on the other to Zozymus by Plat. lobata. 
Genus Cancer, Leach. (Puatycarcinus, Latr., Edw.) 
Antenne externe articulo basilari maximo, anticé in dentem fortem producto, hiatum 
inter frontem et canthum internum oculi implente: portione mobili setacea, brevi, 
propius foveole antenne interne quam cantho interno oculi inserta. 
Antenna interne foveolis longitudinalibus, antrorsum porrecte. 
Pedipalpi externi caulis interni articulo secundo ad marginem antico-internum excavato. 
Pedum par anticum subinzequale, paria reliqua ambulatoria. 
Abdomen maris 5- foemine 7-articulatum. 
Oculi pedunculo brevi. 
Testa transversa, lata, ellipticé arcuata, marginibus antico-lateralibus decem-lobatis, 
lobo posteriore obsoleto ; fronte trifido. 
The shell in this genus is broad, elliptical, somewhat elevated, and with the regions 
rather distinctly marked. The surface in all the species hitherto known is more or 
less granulated. The front is trifid, the middle tooth being sometimes lost in very old 
