300 = MM. Wilson and Crick—The Lias Maristone of Tilton. 
Affinities.—D’Orbigny, in his Prodrome, gives a short diagnosis of 
a fossil, which appears to be rather widely distributed in the Upper 
Lias (étage Toarcien) of the centre and east of France, under the 
name Turbo Patroclus, and the same form appears in the “ Paléonto- 
logie Francaise” as Purpurina Patroclus. Although no description 
is given in the latter work of this or indeed of any other Purpurina, 
it is obvious, from the illustrations in the atlas, that we have here 
our Rutland fossil. Yet the figure in the “ Pal. Frang.” is remark- 
able in this, that with the identical form and ornamentation of 
the English fossil, it presents apertural characters which are very 
different. Instead of the contracted aperture, thickened outer lip, 
and anterior and posterior canaliculation, possessed by our shell, we 
see depicted a large oval aperture with rounded margins and without 
the trace of a groove or canal. Evidently whilst the body of the shell 
of Purpurina Patr oclus, D’Orb., is correctly delineated, the aperture 
is a beautiful but imaginary restoration; and the same observation 
will probably apply to Purpurina Philiasus, D’Orb., which is prob- 
ably only a more highly ornate variety of P. Patroclus. It is true | 
there are other Jurassic Gasteropods which have a spire and orna- 
mentation extremely like P. Patroclus, and which nevertheless 
belong to different groups, eg. Alaria and Pseudalaria; but the 
points of agreement between the fossil here figured and the 
_ illustration in the Pal. France. are, I hold, too precise to leave the 
above identification in doubt. It is to be noted also, that the name 
Purpurina given by D’Orbigny, implies that he considered these 
shells siphonostomatous, and this is expressed also in the original 
diagnosis of the genus, by that author in his “Cours élémentaire 
de paléontolgie,”—‘‘Ouverture pourvue en avant d’un tres étroit 
sillon qui remplace Vechancrure des Purpura.” It will not be 
necessary to give, at this point, the history of Purpurina, the more 
so as this subject was not very long ago treated in some detail by 
my esteemed friend Mr. W. H. Hudleston, F.R.S., in the pages of 
the GronogicaL Magazine,’ and still more recently in the first part 
of his valuable Monograph on the Inferior Oolite Gasteropoda.? It 
is sufficient for my purpose to point out that, whilst Jurassic 
paleontologists have rightly followed Deslongcbamps and Piette in 
restricting the genus Purpurina to forms possessing the general 
characters of Purpurina bellona, D’Orb., continental authors have 
been generally misled in their identification of P. Patroclus, D’Orb. 
as one of the Littorinide (an Eucyclus= Amberleya, or a Littorina), 
by the inaccurate figures in the Paléontologie Frangaise. What 
then are the true affinities of the shell under consideration? In the 
aggregate of its characters—the rather elongate spire, the aperture 
with an expanded outer lip, slightly enveloping last whorl, out- 
wardly twisted columella and clearly defined anterior and posterior 
canaliculation—this peculiar form seems to fall under the Cerithiidee. 
It will scarcely, however, come within the genus Cerithium or any 
other established genus of that family. In certain details of form and 
1 Grot. Mac. Dec. II. Vol. IX. (1882), p. 11. 
2 Pal. Soc. British Jurass. Gast. pt. 1. p. 8, and p. 83. 
