368 Mr. T. H. Withers on the 
XLV.— The Morphology of some Cretaceous Cirripedes. 
By Tuomas H. Wrruers, F.G.S. 
[Plate V.] 
(Published by permission of the Trustees of the British Museum.) 
Turis may be taken as a continuation of my paper on “ Some 
Cretaceous and Tertiary Cirripedes referred to Pollicipes ” 
(Ann. & Mag. Nat. Hist. 1914, ser. 8, vol. xiv. pp. 167-206, 
pls. vii., vill.), While I had the intention later of taking up 
the study of the species included here, the material at my 
command does not allow me at present to deal with them 
in such a comprehensive manner as [ should like ; but the 
fact that a species of this group has to be included in my 
account of the Riigen Chalk Cirripedes has compelled me to 
write the present note. 
In the Cretaceous rocks are found quite commonly certain 
simple types of Cirripede valves that have been in the main 
ascribed to various species of Pollicipes. The geologically 
oldest of these is Pollicipes bronni, Roemer, from the Middle 
Neocomian (Hilsconglomerat) of Essen, Westphalia, hitherto 
known only by the carina, but we are now able to add 
the scutum and tergum (Pl. V. figs. 11, 12). This is 
followed in the Albian by the common Pollicipes unguis, 
J. de C. Sowerby, from the Gault of Folkestone, Kent, and 
Pollicipes imbricatus, Withers, from the Blackdown Beds of 
Blackdown, Devonshire, and in the Chalk by Pollicipes 
glaber, Roemer, and a number of allied species. It would 
appear that P. glaber is the direct descendant of P. unguis, 
and from P. glaber has arisen at different horizons in the 
Chalk a number of forms that are sufficiently distinct to 
warrant authors in giving them specific rank. 
The following are the species considered by me in this 
paper as constituting a single natural group, but when these 
species come to be studied more carefully in detail there is 
no doubt at all that the number will be decreased :— 
Danian—Cenomanian : 
Pollicipes angelini, Darwin (carina and tergum only). 
Scalpellum attenuatum, H. Woodward. 
Pollicipes billaulti, Peron. 
"a conicus, Reuss. 
Pollicipes ? corrugatus, H. Woodward. 
Pollicipes costatus, Kafka. 
- cuspidatus, Kafka. 
