VERRUCA PRISCA. _Bosquet._ Monographie des Crustacés fossiles du
Terrain Crét. de Limbourg, Tab. 1, fig. 1-6; 1853.
_Shell smooth: moveable scutum, with the lower articular ridge somewhat
broader than the upper articular ridge._
Fossil--'Système Senonien et Maestrichtien,' Belgium, Mus. Bosquet;
in Chalk, Norwich, Mus. J. de C. Sowerby.
M. Bosquet has admirably figured and described the several separated
valves belonging to this species, and I owe to his great kindness an
examination of some of them. In Mr. J. de C. Sowerby's collection,
also, there is a single specimen, attached to a Mollusc, with the four
valves of the shell united together, but without the two moveable
opercular valves; it cannot be positively asserted that this is the
same species with that of M. Bosquet, but such probably is the case.
This is the species to which I alluded in the Introduction to my
'Monograph on Fossil Lepadidæ.' It is an interesting species, from
being the only known Secondary one, but in itself it is a very poorly
characterised form, and I can point out no important character in the
shell by which it can be recognised. The rostrum and carina, which are
of nearly equal sizes, are locked together by the usual interfolding
plates, and likewise to the fixed scutum and tergum; but these latter
plates seem to have been less developed in M. Bosquet's specimen than
in the English. The fixed scutum has a large adductor plate, which
seems to have been chipped in M. Bosquet's specimen; this valve and the
fixed tergum in all essential respects resemble the same valves in _V.
Strömia_. The surface of the shell is very smooth.
The _moveable scutum_ has its occludent margin considerably arched:
the lower articular ridge is broader than the upper ridge, in which
respects it resembles the same valve in _V. lævigata_, but the whole
valve is not so broad as in that species. There is no adductor ridge on
the under surface. The _moveable tergum_ has its upper articular ridge
narrow, and slightly produced into a point on the scutal margin: in
this latter respect this species also resembles _V. lævigata_, but the
whole valve is not so broad in proportion to its height.