THE SESSILE BAENACLES. 271 



cf. Form cylindric (hexagonal), the orifice and basis of 

 equal size; basal edges of compartments having small 



teeth, the median one largest Cifl hid role pas, p. 287. 



c^ Orifice nmeh larger than the basis ; basal edges of compartments 

 simple. 



(V. Cnp-shaped, subspherical or shortly cylindric, the 

 parietes with annular ridges interrupted in the middle 

 of each compartment by a smooth longitudinsd area; 

 inner edges of the compartments not fornnng a lobed 

 rim around llie oriflce__ ^icpluniolcpas^ 



(f. Bowl-shaped, with a cellular outer layer ; iiuier layiM* 

 of each compartment forming a thin, rounded lobe at 

 the orifice Siotnaiolepas, p. 28S. 



CoRONULiD Series. Borders of the mantle produced around the 

 oral opeyiinc/ to form a hood over the e'lrr'i; plates of the wall au'lh- 

 011 1 a median, longitudinal sulcus or impression-. Living on Cetaeea. 



Genus CORONULA Lamarck. 



1802. Coromda Lamarck, Annales du Museum National e, vol. 1, p. 464, 



for Balanus diadema, Balanus halccnnris, and Balamis iestndinarius. 

 1817. Diadema Schumachkr, Essai d'un nouveau Systeme Vers Testaces, 



p. 90; monotype, D. vulyaris = Lepas diadema Linnnpus. 

 1817. Diadema Ranzant, Opuscoli Seientifiri, vol. 1, fasc. 4, i). 27G. No 



species mentioned." 

 1817. Cetopirns Ranzani, Opuscoli Seientiliei, vol. 1, fasc. 4, p. 270. No 



species mentioned.^ 

 1825. Polj/lepas Klein, Gray, Annals of Philosophy, new ser., vol. 10, p. 105 



(P. diadema, hei'e selected as type). 

 1833. Coronnlites Parkinson, Organic Remains of a Former World, vol. 3, 



p. 240; monotype, C. diadema Parlcinson (=C. harhara Darwin?). 

 1852. Poljilopas Klein, IMorch, Catalogus Conchyliorum qure reliquit D. A. 



d'Aguirra et Gadea, Comes de Yoldi, p. 66; monotype, F. diadema. 

 1852. Ceieopivus Ranzani, IMorch, Catahigus Conchyliorum qua? reliquit 



D. A. d'Aguirra et Gadea, Comes de Yoldi, p. G7 ; monotype, C. com- 



planafiis Chemnitz. 

 1854. Coronula Darwin, Monograph, p. 397. 

 1895. Flahelcorona De Gregorio, Annales de Geologie et de Paleontologie, 



17 livraison, ]». 5; monotype, Coronula (Plabeleoroiia) pcaraz\::ensis 



De Gregorio. 



Barnacles with six equal compartments around tlie small body- 

 chamber, the parietes bearing four radiating lamellar folds, simple 

 or branching, and terminating in T-shaped flanges, which, l)eing in 

 close contact, form an outer wall and inclose cavities open below, occu- 

 pied by the skin of the host. Radii wide. Basis membranous. Oper- 



1 Sfcphanolepaf) will not be considered further in this work, since the single species is 

 not contaiui'd in the collection of the National Mnseiim. For description see 11. Fischer. 

 Actes do la Societe Linu^'Due do Bordeaux, vol. 40, 1S8G, p. 193. Further uotes and figures 

 are given by A. Gruvel, Nouvelles Archives du Museum, ser. 4, vol. 5, lOOf,, p. HO. Tyjie 

 and solo species &'. nuiricata Fischer, Pulo Condor, Cochin China, in the interstices of Uw 

 dermal plates of TlwlasfiOcheJiis imbricala. 



2 Ui his paper of 1S18 Ranzani supplied types to the genera proposed in the previous 

 year. He descrilied Cetopirus balcrnaria {^Coronula complanata), and Diadema candidum 

 (=C'oronula diademu). No other species of these genera were mentioned. 



