39 
of the Ventriculidse of the Chalk. 
que latere porosum/^ The characters of Ocellaria, as given by 
all the authors*, are clear and unmistakeable so far as they goj 
and there cannot be a moment^s doubt as to what the true rela- 
tions of the so-called genus are, as will presently be seen. It is 
perfectly certain that this so-called Ocellaria ramosa-\ has none 
of these relations, and therefore that it does not serve to bring 
the Ventriculidse within the tertiary period. No trace of this 
family has, then, yet been anywhere discovered higher than the 
upper beds of the English chalk. 
As it is desirable to have the treatment of the subject as com- 
plete as possible, so far as it goes, and as the materials which I 
have collected from the English chalk are sufficiently abundant 
to lead me to hope that such completeness may be given, for all 
practical purposes, to the description of the forms found in those 
beds, I shall confine myself at present to these last ; wffiich I the 
rather do in that, while it w^ould be a priori probable that the 
examination of so extensive a series of beds would at any rate 
afford a full series of typical characters, — and therefore a sound 
basis for a permanent and generally applicable system of classifi- 
cation, — the exammation of the Rhanden specimens in the British 
^luseum has satisfied me that all of them will range within the 
typical groups which the forms of the English chalk have led me 
to assign. 
I have already indicated J in what direction we must look for 
the essential characters which mark this whole family. It is 
extremely improbable that a structure so extraordinary, so pecu- 
liarly bearing the marks of special design and adaptation as 
the octahedral structure, should be otherwise than characteristic 
of the family in individuals of which its existence has been dis- 
covered. Until, then, it has been found elsewhere, the philoso- 
phical inquirer will take that structure as his guide in the deter- 
* Those characters are, " Polypier pierreux, aplati en membrane, diverse- 
ment contourne, subinfundibuliformee, a superficie arenacee, muni de pores 
sur les deux faces.” The observations of Milne-Edwards, on an inspec- 
tion of the actual fossils, are alone sufficient to show that the present fossils 
could not be Ocellarice, their apparent tubules being, as stated in p. 511, 
sometimes penetrated by fibres in a radiated manner. Milne-Edwards 
expressly says (Lamarck, Anim. sans Vert. ii. p. 291), ” L’axe solide, qui 
remplit assez ordinairement les trous, et qui a ete pris pour une partie du 
Polypier lui-meme, n’est que la gangue qui s’est moulee dans ces trous, et 
qui s’est cassee au niveau de la surface du Polypier, lorsque celui-ci a ete 
detache de la masse qui le renfermait.” 
t The fossil is however a very curious and interesting one. Its whole 
aspect and character recall those of the Alcyonium, both in its massiveness, 
its cylindrical tubules, and their connecting plexus of fibres. I have many 
analogous fossils from the chalk, into the investigation of which it is my 
intention to enter when the present subject shall be completed. 
Ante, vol. xx. p. 182. 
