oa 
hie 
Morphology of some Cretaceous Cirripedes. 371 
lower margins subparallel, and the latera! and carinal mar- 
gins almost equal in length, the valve being somewhat 
oblong in shape. 
Distribution. —Albian, Gault; Folkestone, Kent; Dienville 
(Aube), France. 
J. de C. Sowerby (1836, pl. xi. fig. 5*) established the 
species Pollicipes unguis on two valves, which presumably 
represent a rostrum and a carinal latus, and at the same 
time (1836, pl. xi. fig. 5) gave the name Pollicipes levis to a 
carina and two terga which really belong to Pollicipes unguis. 
Darwin (1851, p. 64, pl. iv. fig. 1) for good reasons 
thought it advisable to adopt the name P. unguis in prefer- 
ence to P. levis, and he figured a number of detached valves, 
mostly fragmentary, said by him to belong to a single indi- 
vidual. They comprised ‘‘a carina and pair of terga, 
much mutilated, a rostrum, sub-rostrum, a pair of upper 
latera, a pair of latera of the lower whori from the carinal 
end of the capitulum, and two other latera of this same 
whorl from one side of the rostral end of the capitulum.” 
From Darwin’s statement as to the incompleteness of the 
terga and carina, as well as from the present state of 
the specimens, which are in the Geological Survey Museum, 
registered 31378, it is quite evident that other specimens 
must have been used in the drawing of the figures. The 
carina could not have been drawn from the present fragment, 
for a part is present which is broken off in Darwin’s figure, 
and the terga, which Darwin himself said were much muti- 
lated, must have been very much restored. The upper latus 
is drawn much too symmetrically. None of the figures of 
the lower latera are very accurate, and the subrostrum has 
apparently been lost, since it is not with the other valves. 
With regard to the lower latera, Darwin further said 
(1851, p. 66) : “these consist of two small [attached] valves 
(/, k), namely (judging from the position in which, over- 
lapping each other, they were embedded), the first and 
second, or more probably the second and third right-hand 
rostral latera of the lower whorl; and a pair (A, 2) (right- 
hand and left-hand) of latera, of about twice the size of the 
two anterior ones, which must have come from the carinal 
half of the whorl, but the exact position of which I cannot 
eli.” 
Concerning the number of valves, Darwin said (1851, 
p- 67): ‘‘ With respect to the number of valves in the whole 
capitulum, it is almost useless to speculate: we have two 
scuta, two terga, two upper latera, two rostra, and we may, 
perhaps, infer two carinwe, making ten valves, we know of 
