10 BRITISH JURASSIC GASTEROPODA. 



(Eucyclus, Desl.) should be placed amongst the Littorinidse, and it is in that family 

 that most systematists have placed the genus. Nevertheless, Terquem and 

 Jourdy, Zittel, and Fischer are opposed to this view, and replace Amberleya in its 

 old position amongst the Turbos. The latter author observes, " The various 

 forms grouped under the generic name Amberleya have the appearance of Tedaria, 

 of Echinella, and of Littorina, but the existence of a nacreous layer, ascertained 

 to exist in the Jurassic Amberleyas, has shown their affinity with the Turbinidae 

 and the Trochidas." I am not aware that any traces of a nacreous layer have 

 been found in our British Amberleyas, but such is stated to be the case in the 

 Jurassic of Moscow (Fischer quoting Zittel). Whilst quite prepared to admit that 

 neither the diagnosis of Lycett nor of Deslongchamps is quite satisfactory, I am 

 at present content to follow Prof. Tate in retaining Amberleya amongst the 

 Littorines, the more so as this classification has the sanction of Stoliczka. 

 At the same time I must repeat my belief, already expressed with regard to 

 Purjpurina, that some of these old genera probably possessed characters which are 

 now rarely, if ever, combined in the same group at the present day. Hence the 

 impossibility of a classification which will satisfy everybody. In the meantime, 

 should any more decided proofs of the existence of a nacreous layer in these very 

 handsome shells become available, it is not too late to alter the position of the 

 genus. 



In some respects there are characters of resemblance between the Purpurines 

 and the Amberleyas, which may be more nearly related than has hitherto been 

 supposed. As I wish to act as far as possible on the principle of precedent no 

 change should be made for which I cannot quote a good authority in justification. 

 But it has occurred to me that d'Orbigny may not have been so far wrong in 

 placing these shells amongst the Turbos, and that possibly they might be made to 

 constitute a sub-family of the Turbinidae. 



But such changes are not to be lightly made, and I should, moreover, always 

 desire to uphold the decision of Morris and Lycett in the majority of doubtful 

 cases. It is satisfactory to believe that, on the whole, their genera find favour 

 with systematists such as Tryon in America and Fischer in France, although not 

 seldom the family position of these has been changed. Morris and Lycett repre- 

 sented an age in the history of molluscan palseontology, when numerous forms 

 hitherto unknown had to be located as best might be under the exigencies of the 

 case. In conjunction with their illustrious contemporaries on the Continent of 

 Europe they succeeded in defining most of the generic groups required for the 

 Lower Oolites, and it is a satisfaction to think that if it should be necessary to 

 split up an inconveniently large genus into sub-genera or sections, for the Lower 

 Oolites at any rate, few if any additional genera are likely to be required. 



The following Table shows the systematic position of certain genera of the 



