30 T. II. Withers — Cirripedes from the Chalk. 



L. Icevissima, Zittel (1884, p. 589, fig. 4), from the Upper Chalk of 

 Diilrnen, Westphalia, in that the scutum is much hroader in proportion 

 to its length, and in the umho being situated in a much more central 

 position, L. Darwini, H. Woodward, differs from L. expansa in the 

 upper portion of the valve being much narrower and attenuated, and 

 in the smaller convexity of the occludent margin. Moreover, the umbo 

 is situated nearer the apex, and is much more prominent : a feature of 

 phylogeuetic importance. 



In the primitive forms of Loricula, the umbo of the scutum must 

 have been apical and the growth of the valve directed downwards. 

 L. Darwini, H. Woodward, from the Turonian (Rhynchonella cuvieri- 

 zone), is a further advance in "which the growth of the scutum has been 

 directed both downwards and upwards beyond the umbo, which is 

 situated a short distance from the apex. The umbo is still prominent, 

 and the upper portion of the valve is much attenuated. L. expansa, 

 which comes from the Senonian (Actinocamax quadratics - zone) , a much 

 higher horizon, represents a still further stage in the development of 

 the scutum, as might be expected. In this form the umbo is in 

 a more central position, slightly nearer the base of the valve, and since 

 the portion of the valve above the umbo is developed to a greater 

 extent and is wider than in L. Darivini the umbo is consequently 

 inconspicuous. 



In conclusion, I have to express my indebtedness to Dr. H. P. 

 Blackmore for allowing me to describe these specimens, and to thank 

 Dr. F. A. Bather, Dr. W. T. Caiman, and Mr. C. P. Chatwin for help 

 in connexion with this paper. 



References to Authors consulted. 



BosauET, J". (1854). "Les Crustaces Fossiles du Terrain Cretace du Duche de 



Linibourg " : Verhand. Comm. Geol. Beschr. Kaarfc Nederland, ii, pp. 13-137, 



pis. i-x, 1 table. 

 (1857). " Notice sur quelques Cirripedes recemment decouverts dans le Terrain 



Cretace du Duche de Limbourg." 4 to. Harlem, pp. 36, 3 pis., 1 table. 

 Darwin, C. R. (1851). " A Monograph on the Fossil Lepadidse, or, pedunculated 



Cirripedes of Great Britain" : Palajontographical Society, London, pp. vi, 88, 



5 pis. 

 (1854). "A Monograph on the Sub-class Cirripedia, the Balanidse, Synopsis 



et Index Systematicus " : Ray Society, London, pp. 684, 30 pis. 

 Fritsch, A. J., & Kafka, J. (1887). " Die Crustaceen der Bohnuschen Kreide- 



forniation." 4to. Prag. pp. 53, 10 pis. col., text-illust. 

 Marsson, Th. (1880). " Die Cirripedien und Ostracoden der weissen Schreibkreide 



der Insel Riigen " : Mittheil. aus dem naturwiss. Vereinevon Neu-Vorpommern 



und Riigen, xii, pp. 1-50, pis. i-iii, 1880. 

 Peron, A. (1888). " Notes pour servir a l'Histoire du Terrain de Craie dans le 



Sud-Est du bassin Anglo-Parisien " : Bull. Soc. Sci. Yonne, xli, 1887, 



pp. 145-224, August, 1887 ; pp. 225-336, pis. i-iii, March, 1888. 

 Roemer, F. A. (1840-1). "DieVersteineruugen des Norddeutschen Kriedegebirges." 



4to. Hannover. 1st Lief., pp. 48, pis. i-vii, 1840 ; 2nd Lief., pp. 97, pis. viii- 



xvi, 1841. 

 Sowerby, G. B. (1843). "Description of a new Fossil Cirripede from the Upper 



Chalk near Rochester" : Ann. Mag. Nat. Hist., ser. i, xii, pp. 260-1, figs. 1, 2. 

 Sowerby, J. de C. (1829). "Mineral Conchology of Great Britain." London. 



vi, pp. 221-2, pi. 606. 

 Steenstrup, J. (1837). "Om Forwerdenens Dyrarter af de tvende Familier 



Anatiferidse (Gray) og Pollicipedidae (Gray) ": Kroyer, Naturhistorisk Tidsskrift, 



i, pp. 358-66. 



