100 
CARDIUM alaeforme. 
TAB. DLIL— fig. 2. 
Spec. Char. Triangular, ventricose, longitudinally 
ribbed ; anterior side truncated, produced near 
the hinge, concentrically ribbed ; posterior side 
much produced, compressed, ribbed. 
This approaches much to Cardium hibernicum in ge- 
neral aspect ; but it has no sharp keel, and the anterior 
side is strongly ribbed. The posterior side is so pro- 
duced as to form a kind of lobe, which improves the re- 
semblance the outline has to a wing. The ribs upon the 
central part of the anterior side diverge from one of the 
longitudinal ribs on each margin of it ; the ribs upon the 
other parts are very close, and alternately large and 
small ; the cast has only the larger ribs. 
The specimens figured are from Queen’s County, Ire- 
land : the same species has also been found at Scarlet on 
the Isle of Man, by Mr. Henslow ; in both places in dark 
coloured foetid Limestone. 
CARDIUM hibernicum. 
TAB. DLII.— 3. and TAB. LXXXIL— 
fig- 1, & 2. 
We here give a representation of a part of this fossil 
which had formerly escaped notice, — the remarkable ex- 
tension of the keel around the anterior portion of the 
shell, to which, if perfect, it would give the form of a 
cup with a broad bottom ; this keel is of a cellular struc- 
ture, the cells long and placed transversely. 
