100 ri^ETACEOUS LAMELLTBRANCHIA. 



Measnrements : 



(1) 



(2) 



77 



102 mm. 



25 



09 



Lono'th ....... 



Height ....... 



(1) and (2) from Devizes. 



Affinities. — This species belongs to a section of Modiola characteristic of the 

 Jurassic rocks, of which M. Soirerhi(tiia (d'Orbigny) [= M. pJirafn, So-\verby], 

 M. perplicafa (Etallon), M. Medns (d'Orbigny), and M. icaunensis (de Loriol) are 

 well-known representatives. 



I have seen only three English examples, and these, althongh in the form of in- 

 ternal casts, seem to agree perfectly with the types of M. flageUifera, Forbes (from 

 Pondicherry), with which I have compared them. Zittel has referred to this species 

 a form found in the. Gosau Beds, of which I have seen one specimen collected by 

 Mr. H. Kynaston from Finstergraben, and now preserved in the Woodwardian 

 Museum ; this also agrees with the Forbes' types. 



The specimen figured by Matheron as Tnoceramus siliqua is probalily an imper- 

 fect example of this species. Modiola GiUieroni (Pictet and Campiche),^ from the 

 Valangian of Presle (near Bienne) and Cinquetral, appears to differ from M. Jiaijel- 

 lifera in having fewer ribs dorsally, and in the general absence of bifurcation as 

 they curve on approaching the carina. 



M. Baini, Sharpe," from Sunday River (South Africa), apparently differs from 

 M. fiageUifera in having the ribs continued ventral to the carina, and perhaps also 

 in having a more elongate shell. 



M. Ehrayi, de Loriol,^ is probably another related form, but at present is im- 

 perfectly known. 



Typps. — From the Valudayoor Group of Pondicherry, preserved in the Museum 

 of the Geological Society of London (No. 10631) ; these are also figured by 

 Stoliczka. 



Distribution. — Upper Greensand of Devizes and Black Ven. 



Modiola undulata (Forhes). Plate XVII, fig. 3. 



1845. Cypricardia ? undulata, E. Forbes. Quart. Jouru. Geol. Soc, vol. i, 



p. 242, pi. iii, fig. 1. 

 1848. Cypricardia undulata, H. G. Bronn. Index Palseont., vol. i, p. 387. 



1 "Foss. Terr. Cret. Ste. Croix" ('Mater. Pal. Suisse,' ser. 4), 1867, p. 503, pi. cxxxiii, 

 figs. 9, 10. 



2 'Trans. Geol. Soc.,' ser. 2, vol. vii (1856), p. 193, pi. xxii, figs. 2, 3. 



' " Faune du Gault de Cosne " (' Mem. Soc. Pal. Suis.oR,' vol. ix, 1882), p. 80, pi. ix, figs. 18—20 

 (especially fig. 20). 



