10 BRITISH JURASSIC GASTEROPODA. 
(Eucyclus, Desl.) should be placed amongst the Littorinide, 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 Tectaria, 
of Hchinella, and of Littorina, but the existence of a nacreous layer, ascertained 
to exist in the Jurassic Amberleyas, has shown their affinity with the Turbinide 
and the Trochide.” 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, | 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 
Purpurina, 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 Turbinide. 
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 paleontology, 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 
Kurope 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 
