20 EOCENE MOLLUSCA. 
SCROBICULABRA. S. Wood. 
When Mr. Morris described §. Condamini he was at a loss to know in what genus 
to place it; and not being able to see the hinge, he referred it provisionally to 
Psammobia. 
M. Deshayes, in describing Ziracia Bazini, considered it as not improbably the same 
shell as that described by Prof. Morris as Psammobia Condamini, although presenting some 
differences in exterior form which induced him to give it provisionally under a different 
specific name; and being, for a similar reason as that which influenced Mr. Morris, 
uncertain as to the genus he preferred rather to place it among Zhracia. 
Mr. Meyer has sent me several valves of Condamini, but they are all of them so 
fixed with the interior downwards in the indurated material as to preclude the 
possibility of the hinge being seen, but a single specimen of a shell so closely resembling 
Condamini in its peculiar external form as to leave little doubt of its being another 
species of the same genus has had the hinge worked out, so as to show pretty nearly its 
true characters ; and I find that this does not correspond with the hinge of either of the 
genera to which Condamini has been thus referred, nor indeed does it strictly accord 
with any genus known to me. It will be seen from the specimen of Dulwichiensis 
figured (which is the right valve) that the hinge has a depression for the cartilage or 
connector sloping towards the posterior side, and there is also a very small slit at the 
umbo through which probably the cartilage protruded, and a similar slit may be seen 
in the genera Thracia, Scrobicularia, and Abra. Our fossil has also two large cardinal 
teeth diverging from the umbo at different angles ; but it has no lateral teeth, and in that 
respect it differs from dra; and although it has not quite so large or expanded a 
depression for the cartilage as Scrodicularia, yet in respect of its hinge it corresponds 
most nearly with that genus, appearing to be intermediate between it and Adra, having 
probably the habits of the former. I have in consequence erected the genus Serodiculabra 
for its reception. Mr. Bott’s specimen has unfortunately the interior nearly filled with 
indurated material, which obscures the muscle marks; and as this cannot be removed 
without danger to the integrity of the specimen, I am unable to give a proper diagnosis 
of the genus in question, and therefore prefer, beyond what is said above, not giving any 
rather than what might prove a partially incorrect one. The interior connector, like those 
of Mactra, Mya, and Thracia, has a slight extension outwardly, as if in those genera the 
compression and expansion of the cartilaginous connector were not quite sufficient for 
the purpose of the animal, without the assistance more or less of the external ligament 
to enable it to keep the margins apart. 
