ADDITIONS. 425 



is nearly flat, and tlie broad radial ribs arc much less distinct than on the left 

 valve; numerous fine concentric ribs are present, and are widely spaced on the 

 early part of the valve, but become closer together on the later part. 



Pecten (CnLAMYs) rKRTOSUS, Defrrnicr. 



Vol. J, p. 170, line 17, delete "Clarendon antl Aldei'bni'y (Halisbniv)." 



Pecten (^quiiecten) cAsnwKiKNSis, irOrhigiii/. [Vol. I, p. 192.] 



A specimen of this species has been found by Dr. Rowe in the zone of 

 Micraster cor-tesludiiuifiiiiii of Dover. 



LiM.\ (LiMEA?) sp. Plate LXI, fig. 19. 



[Omitted from Vol. II, p. .52.] 



A few examples of a species which resembles Limea (jraiinlatissiimt, Wollemann,' 

 have been found in the Speeton Clay (zone of Bdemuites httcnilis) of Speeton. 

 Only a young individual is figured by Wollemann, so that exact comparison 

 cannot l)e made at present. 



Suh-r/enus — PsEunorTEUA, Meel\ 



AYhen descriljing the species of rseiuloptera (pp. G-j-OD) I regarded it as a 

 sub-genus of Pterin. Ligament-pits have not been seen in any English specimens, 

 but their presence was noticed l)y Gueranger- and by Peron^ and indicates that 

 Pseudoptera cannot be associated witli Pfcriu, but shoidd prol)ab]y l)e regarded as 

 a sub-genus of GcrviUia. 



Gei!Vii.m.\ Forbesiaxa, (rO)7%Hy. 



[Vol. II, p. 85, pi. xi, figs. 26, 27 ; pi. xii. figs. 1-5.] 



This species belongs to the sub-genus Ensigervilleia of Dietrich.' 



1 'Bivalv. 11. Gastrop. J. deutscli. ii. liolluucliseli. Noocoms ' (1000), p. 37, pi. ii, figs. 4, 5. 

 -' 'AUnim Paloont. aelaSaithe' (1807), pp. 17, 20, pi. xxii, figs. 9, 10; pi. xxv, figs. 10, 11 

 "Woods, 'Palaeont. U. Cict. N. Nigeria' (1911), p. 278, footnote 1. 



3 "Descript. Bnuli. elc, Terr. Crct. Timisie" (1890—91), p. 238. 

 * 'Ceutralbl. fiir Miu., etc' (1910), p. 235. 



