422 CRETACEOUS LAMELLIBRANCHIA. 



Marl (zone of ScJdmnbachia varians) of Ventnor and Folkestone. Zone of Holaster 

 subglobosus of Burham and Lewes. Zone of BhynchoneUa Guvieri of Dover. 

 Zone of Terebratulina lata of Wouldham. Zone of Holaster planus of Morgan's 

 Hill, Wiltshire. 



Durania sp. cf. austinensis (Romer), 1852. 



1855. Radiolites Mortoni, S. P. Woodward. Quart. Journ. Geol. Soc, vol. xi, 



p. 59, pi. v, figs. 1, 2. 

 1004. Biradiolites austinensis, H. DouvilU. Mission Sclent. Perse. Ill, 



Etudes geol. iv, Paleont., 

 p. 257. 

 1909. Sauvagesia austinensis, A Toucas. Classific. et Evolut. des Radiolitides 



(Mem. Soc. geol. de France , Pal- 

 eont., vol. xvii), p. 96, fig. 64. 

 1912. Durania austinensis, C. F. Parona. Mem. R. Accad. Scienze di Torino, 



ser. 2, vol. lxii, p. 287, pi. ii, fig. 4. 



Remarks. — In the specimen from the Upper Chalk figured by Woodward the 

 siphonal bands are much broader than in Durania Mortoni, and the ribs on the 

 convex interband are finer and more widely separated. The parts recognised by 

 Toucas as siphonal bands were regarded by Woodward as the surfaces to which 

 other individuals had been attached. 



This species has been identified with Romer's Hippurites austinensis from Texas 1 

 by the authors quoted above, but, as Prof. Douville now points out, this identifi- 

 cation must be regarded as uncertain since the essential characters of Romer's 

 species are not yet known. 2 The finer structure of the outer layers of the shell 

 cannot be taken as a distinguishing feature of Romer's species. 



Type. — Woodward's specimens from Rosherville are in the British Museum. 



Distribution. — Zone of Micraster cor-angidnum of Rosherville, near Gravesend. 



1 Romer, ' Kreidebild. v. Texas ' (1852), p. 77, pi. vi, fig. 1. 



2 A few specimens show indications of the ligamental ridge and appear to belong to the genus 

 Sauvagesia, e. cj. British Museum No. 33957 from the zone of Holaster subglobosus of Sussex, and No. 

 L. 4842 from the Turonian of Dover. 



