64 FOSSIL CIRRIPEDIA. 
the measurements of the Gravesend specimen: the scutum is too much broken to be 
measured, and the breadth only of the basal margin of the carina can be given—it is °25 of 
an inch; the terga are nearly °8 long and fully ‘4 broad. The upper latus is -27 in height, 
basal margin °23 in length. Lower latus ‘2 in height and -26 in breadth. I imagine 
that the broken scutum belonging to this individual, was fully two thirds of the size of the 
largest scutum which I have seen, namely, that from Sarstedt, -6 of an inch in length. 
Affinities. From the very close affinity of this species to the following one, P. unguis 
of the Gault, we may safely infer that it had not only a rostrum (of which a specimen found 
separately has been described), but also a sub-rostrum ; whether it had a sub-carina, as is 
probable, must remain doubtful. The two faint ridges running from the umbo of each 
scutum to its basal margin, probably mark the extent to which this valve was overlapped, ~ 
as in the case of the recent P. mitel/a, by the rostrum and upper latera; and the ridge on 
the terga, steep towards the carina, probably shows the extent to which this latter valve 
reached. It is also probable, as we shall see under the head of P. waguwis, that there was 
only one whorl of valves under the upper latera, and that this included the sub-rostrum : 
the latera in this lower whorl were probably not very numerous, but large, and of very 
unequal sizes; their mutual overlapping no doubt caused the oblique ridges on their 
exterior surfaces. 
12. Pouuicipes uneuis. Tab. IV, fig. 1. 
PoLtictrEs uNGUIS. J. Sowerby. Geolog. Transac. 2d series, vol. iv, t. xi, fig. 5*. 
_- LEVIS. Ib. Ib. Ib. fig. 5 (sed 
non Tab. xvi, fig. 1,—alia species). 
P. scutis incognitis, verisimiliter ut in P. glabro.  Margine basali carine obtusé 
acuminato, sub-rotundato. Lateribus superioribus: elongatis triangularibus, dimidium lon- 
gitudinis tergorum superantibus. Lateribus anticis inferioribus costd subcentrali instructis. 
Scuta unknown, probably as in P. glaber. Carina, with the basal margin, bluntly 
pointed, somewhat rounded. Upper /atera elongated, triangular, exceeding half the 
length of the terga. Anterior lower latera, each with a ridge, subcentral. 
Gault ; Folkstone, (common.) Burham, Eastweare Bay, Maidstone. Mus. Practical Geolog., Bower- 
bank, J. Sowerby, Brit. Mus., &e. In the Museum of Geolog. Soc. there is a tergum of this species, 
marked Lower Greensand, Maidstone. 
General Remarks. This species comes very close to P. glaber, but can, I think, be 
safely distinguished from it, even with our present materials. A specimen most unusually 
perfect is in the Museum of Practical Geology ; it consists of a carina and pair of terga, 
much mutilated, a rostrum, sub-rostrum, a pair of upper latera, a pair of latera of the 
lower whorl from the carinal end of the capitulum, and two other latera of this same 
