131 
Note on the Subgenus Limea, Bronn. 
By Joun Lycert, Esq. 
Reap 28truH AvcusT 1855. 
THE present note is intended to direct attention to a peculiarity 
connected with the external surface of Limea, trivial in its zoo- 
logical importance, but which is calculated from its persistency 
to be a useful aid to the paleontologist in the absence of hinge 
characters. 
The subgenus Limea has hitherto been distinguished from 
Lima solely by the presence of a series of parallel teeth upon 
each side of the hinge-plate, a feature which cannot be ascer- 
tained in the majority of specimens ; and the only British species 
of Limea hitherto described has so little in its general aspect to 
separate it from the young condition of Lima duplicata (a shell 
which is associated with it in the same beds), that any clear ex- 
ternal distinction which can be ascertained between them is 
worthy of notice, more especially when it will also be found to 
characterize Limea as a subgenus. 
It is in the auricles that the distinctive feature resides, and it 
is immediately connected with the hinge-plate beneath: it will 
be found that the radiating lines which usually ornament the 
surfaces of the auricles in the Pectens and Lime also exist in 
Timea, but that in the latter they abruptly disappear towards the 
outer angle of each auricle, leaving a small triangular smooth 
area, which is traversed transversely downwards and inwards by 
a few elevations ; these are placed immediately over and corre- 
spond to the grooves which separate the teeth upon the hinge- 
plate. In all well-preserved specimens this kind of surface is 
visible upon one or both of the auricles, its distinctness depend- 
ing upon the condition of the specimen with reference to fossi- 
lization and the greater or less prominence of the internal 
features. 
Limea duplicata is abundant in the shelly oolite of Leck- 
hampton Hill; there is also another more ornamented but un- 
described species higher in the same formation, and found at 
many localities in the upper Ragstones of the Cotteswold Infe- 
rior Oolite. The peculiarity of the auricles is observable equally 
in both these species. 
VOL. Il. “M 
