294 i^LIOCENE MOLLUSCA. 



Odliner with the B. assimilis of Prof G. 0. Sars, and he has sent me a typical 

 specimen from the Stockholm Museum, with which he considers it to correspond. 

 The latter authority says that this shell approaches nearest to B. rugidata, but 

 differs from the latter in its more slender form, its stronger keel and its elongated 

 spire. I adopt the reference of the Butley shell to Prof. Sars' species, B. assimilisy 

 on Dr. Odhner's authority, but as that term was used by Wood in 1872 for a Bela 

 from the middle glacial sands of Billockby, it is necessary to adopt for it another 

 name. I dedicate it, therefore, to Dr. Odhner, in acknowledgment of his kind 

 assistance in the comparison of this interesting group of Crag fossils with 

 the typical specimens in the Museum at Stockholm, and in their identification with 

 the northern species recognised by Scandinavian conchologists. 



He informs me that the present shell is the typical Tritonium turricida of 

 Loven. Prof. Kobelt agrees with Prof. Sars, Messrs. Dautzenberg and Fischer, 

 and Dr. Odhner, in considering it specifically distinct from B. rugidata. It belongs, 

 however, to the rugidata group. 



Bela Trevelyana (Turton).i Plate XXXII, figs. 30—33. 



1834. Pleurotoma Trevellianvm, Turton, Mag. Nat. Hist., vol. vii, p. 351. 



1848. Clavatula Trevelliana, S. V. Wood, Mon. Crag Moll., pt. i, p. 63, pi. vii, fig. 14. 



1868. Mangelia (Bela) Trevelliana, Forbes and Hauley, Brit. Moll., vol. iii, p. 452, pi. cxii, figs. 1, 2. 



1867. Pleurotoma Trevelyana, Jeffreys, Brit. Couch., vol. iv, p. 398, pi. xci, fig. 8. 



1878. Bela Trevelyana, G-. O. Sars, Moll. Eeg. Arct. Norv. p. 235, pi. xvi, fig. 13. 



1884. Bela Trevelyana, Morch and Poulsen, MS. list in Greological Museum, Copenhagen, no. 41 



(unpublished). 

 1886-1901. Bela Trevelyana, Friele, Norske Nordh. Exped. (MoUusca), pt. ii, p. 11, pi. viii, figs. 7—10, 



1886 ; pt. iii, p. 91, 1901. 

 1899. Bela Trevelyana, Posselt, Medd. om Grroul., vol. xxiii, p. 154. 



1900-1. Bela Trevellyana, Br^gger, Norges geol. unders^gelse, vol. xxxi, p. 653, pi. xvi, fig. 20. 

 1905. Bela Trevelyana, Kobelt, Icon, schalentrag. europ. Meeresconch., vol. iii, p. 266, pi. ixxxv, 



tigs. 19, 20. 

 1910. Bela Trevelyana, Odhner, Kongl. Svensk. Vet.-Akad. Handl. Stockholm, vol. vii, p. 10. 

 1912. Bela reticulata, Dautzenberg et Fischer, Camp. Scieut. Pr. Monaco, vol. xxxvii (Mollusques), 



p. 46. 



Specific Characters.— ^heW ovato-fusiform, subventricose ; whorls 6, rounded, 

 distinctly but slightly keeled, the last much the largest ; ornamented by numerous 

 fine and inconspicuous longitudinal ribs, crossed by fine spiral striae which decussate 



1 Messrs. Dautzenberg and Fischer consider, and possibly with reason, that the present species is 

 identical with that described by Brown in 1828 (111. Conch. Gt. Brit., pi. xlviii, figs. 29, 30) as 

 Pleurotoma reticulata, which name, by the strict law of priority, should be substituted for B. Trevelyana. 

 The latter has been so widely and universally adopted for nearly a century, however, that it seems to 

 me inexpedient to alter it. Jeffreys regarded Brown's name as " obsolete." 



