THE SESSILE BARNACLES. 273 



I) 1 . Convexly conic, depressed, the parietal ribs flat, beautifully bonded ; ribs 



in tbe base having few, not symmetrical branches C. rcitinu; p. 275. 



a*. Body-chamber very shortly barrel-shaped or cylindric, the basal opening at 

 least as large as the orifice; sheath decidedly shorter than the inner wall, 

 its basal edge not overhanging; ribs along the sutures, in the base, having 

 several symmetrically arranged branches in adult individuals; radii almost 

 as thick as the compartments; opposed edges of the terminal flanges of the 

 ribs roughened but not crenulate ; form depressed. Subgenus Cctopirns. 



C. complanata, p. 27G. 

 Pliocene species of Coronula. 



Coronula barbara Darwin (Monograph, p. 421), of the British Red 

 Crag, is related to G. diadema, but the spaces below the radii are 



solidly filled up. 



Coi'onula bifid a 1 has not been very clearly distinguished from 

 C. barbara.' 2 Diadema diluviana O. G. Costa 3 appears from the 

 figures to be either C. bifida or O. barbara. 



Coronula ficarazzensis De Gregorio, referred to above under the 

 perfectly useless subgenus Fhtbclcorona, is a form very close to 

 C. regime Darwin; whether identical or not requires a comparison 

 of specimens to tell. 



CORONULA DIADEMA (Linnaeus). 

 Plate 65, figs. 3, 4. 



1767. Lcpas diadcina LINNAEUS, Systeuia Naturse, ed. 12, p. 1109 (see 



Hanley, The Shells of Linmeus, p. 20). 

 1776. Lcpas balwnaris O. F. MULLEB, Zoologies Danica. 1'rodromus, p. 250, 



No. 3024. 



1778. Balanus bala'na DA COSTA, Hist. Nat. Test. Brit., p. 251. 

 1780. Lcpas bala-naris O. PABEICIUS, Fauna Grceulandica, p. 425. 

 1790. Lcpas balanaris GMELIN, Systema Naturse, ed. 13, p. 3208. 



1817. Diadcina rulyaris SCHUMACHER, Essai d'un nouveau Syst. Vers 

 Testaces, p. 91. 



1818. Diadema eaiididuin HANZANI, Opuscoli Scientific}, vol. 2, p. 88. 

 1818. Coronula diadcina Linnaeus, LAMARCK, Hist. Nat. Anim. sans Vert., 



vol. 5, p. 387. 

 1825. Polylepas (Diadcina) klcinii GKAY, Annals of Philosophy, new ser., 



vol. 10, p. 105. 

 . Coronula diadema Lamarck, CHENU, Illustration Conchyliologiques, 



pi. 1, fig. 3 ; pi. 2, fig. 3 ; pi. 3, fig. 5. 

 1854. Coronula diadema Linnaeus, DARWIN, Monograph, p. 417, pi. 15, figs. 



3, 3ff, b; pi. 16, figs. 1, 2, 7. 

 1870. Coronula biscayensis VAN BENEDEN, Bull, de 1'Acad. Roy. des Sci. 



ties Lettres, et des Beaux-Arts de Belgique, ser. 2, vol. 29, p. 349. No 



description. 

 1870. ? Diadema japonica VAN BENEDEN, Bull, de 1'Acad. Roy. des Sci. 



des Lettres, et des Beaux- Arts de Belgique, ser. 2, vol. 29, p. 354. 



Named, but not described, from a Japanese drawing. 



1 Bronn, Italiens Tertilir-Gebilde, 1831, p. 126. 



2 de AlessandH, Palwontographica Italica, vol. 12, 1006, p. 315. 



3 Di alcuni Balanidi app. al Regno di Napoli, in Atti Accad, Sci. Napoli, vol. 5, pt. 2, 

 1843, p. 120, pi. 1, fig. 7. 



