CUSPIDARIA. 261 



Affinities. — When describing the Molhisca of the Chalk Rock in 1897 only an 

 imperfect specimen of G. jii'lcJira was available for study, and I identified it with 

 C. caudata (Nilsson). Two better specimens from Norwich have now been seen, 

 and a new figure of Nilsson's type has been published by Hennig.^ The English 

 form — figured by Sowerby as LedajntJchra — differs from the type of C. caudata in the 

 relatively greater height of the anterior part of the shell, the more nearly posterior 

 position of the umbones, and in the posterior rostrum proceeding from the level 

 of the hinge-line instead of below it. G. jjulchra approaches closely the specimen 

 figured by Goldfuss ^ as C. caudata, and it was chiefly on account of this resem- 

 blance that I identified the English form with Nilsson's species. Stoliczka^ and. 

 Hennig, however, consider that Goldfuss' specimen is not an example of C. caudata. 

 If all the specimens figured by foreign writers as G. caudata really belong to that 

 species then it is obviously extremely variable and might well include G. pidchra. 

 Without an opportunity of studying a series of foreign specimens and a larger 

 number of English examples it seems, at present, preferable to regard G. pulcltra 

 as distinct from G. caudata. None of the English specimens shows evidence of the 

 existence of such a long posterior beak as is present in the type of G. caudata. 



A specimen of Gusjndaria from the Upper Greensand of Devizes (Plate XLIV, 

 fig. 7) resembles some specimens of G. pdchra and may be provisionally referred 

 to that species. 



Type. — The type, from the " Chalk of Kent," cannot now be found. 



Distribution. — Chalk Rock of Cuckhamsley, Berkshire, and Henley Park. 

 Upper Chalk (zone of Belemnitellaj mucronata) of St. Giles' Gate and Horstead, 

 near Norwich. 



1 ' Eevis. Lamellibr. i Nilsson's Petrific. Suecana Format. Cret.' (1807), p. 62, pi. iii, fig. 28 ; 

 Eavn, ' Mollusk. i Danmarks Kridtafl. I. LameUibr.' (1902), p. 65 [133], pi. iv, fit;. 24. 



" ' Petref. Germ.,' vol. ii (1840), p. 251, pi. cli, iig. 17. Compare also Wolieinaun, ' Seuons v. 

 Biewende' (' Jahrb. d. k. preuss. geol. Landesanst.,' fiir 1900), p. 23, fig. 5 ; Midler, ' Mollusk. d. 

 Uutersen. v. Braunschweig u. Ilsede ' (1898), p. 77, pi. x, figs. 10, 11 ; Wolleuiaun, ' Fauna der Liine- 

 burg. Kreide' (1902), p. 80. 



2 ' Palseout. Iiidica, Cret. Fauna S. India,' vol. iii (1870), p. 41. * 



35 



