368 iMr. T. 11. Wilher.-A o» ihe 



XLV. — The Morpholof/ij of name Cretaceous Cirripedes. 

 \}\ Thomas 11. Withers, F.G.S. 



[Plate v.] 



(Published by permission of the Trustees of the Piitish Museum.) 



This may be taken as a continuation of my ))aper on " Some 

 Cretaceous and Tertiary Cirripctics referred to Po/Iicipes^^ 

 (Ann. & Mag. Nat. Hist. 1911, ser. 8, vol. xiv. pp. Hir-.'iOG, 

 pis. vii., viii.). Wliile I liad the intention later of taking up 

 the stud}' of the species included here, the material at my 

 command does not allow me at present to deal with them 

 in such a com|)rehensive manner as I 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 

 Mi'ite 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 (llilsconglomerat) of Essen, "Westphalia, hitherto 

 known only by the carina, l)ut we are now able to add 

 the scutum and tergura (PL V. figs. 11, 12). Tliis is 

 followed in the Albian by the common Pollicipes unguis, 

 J. de C. Sowerby, from the Gault of Folkestone, Kent, and 

 Pollicipes imhricntns, Withers, from the Blackdown Beds of 

 Blackdown, Devonsliire, and in the ('halk by Pollicipes 

 glaber, Roemer, and a number of allied species. It Mould 

 appear that P. ylaber is the direct descendant of P. unguis, 

 and from P. gtiiber 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 i'ollo\\ing are the species considered by me in this 

 paper as constituting a single natural group, Ijut when these 

 species come to be studied more caretuUy in detail there is 

 no doubt at all that the number will be decreased : — 



Danian — Cenomanian : 



Pollicipes angelini, Darwin (carina and tergum onl}"^). 

 Scatpelium attenuatnui, II. Woodward. 

 Pollicipes billaulli, Peron. 



„ conicus, Reuss. 

 Pollicijjes? corrugaius, H. Woodward. 

 Pollicipes costutus, Kafka. 



„ cuspiilatus, Kafka. 



