of the Chalk. 77 



of the muscular envelopment arise innumerable tubuli, which 

 pass direct to the ventricular cavity, and terminate in openings 

 on its surface. In some specimens a substance of a sponge-like 

 appearance fills up the interstices between the tubuli, and pro- 

 bably is the remains of a membrane which served in the recent 

 animal to connect the tubes and assist in strengthening and 

 uniting the whole mass. The sides of the ventricular cavity are 

 generally about one-third of an inch in thickness. From the 

 bases or pedicle proceed fibres by which the animal was attached 

 to its appropriate habitation." 



The portions of the structure here described as internal, and 

 considered by Dr. Mantell to be absorbents, are in the ' Wonders ' 

 and ' Medals ' of Dr. Mantell considered as polyp cells, and the 

 animal described as a composite and not a single one. I shall 

 show that each appropriation of those so-called tubuli is erro- 

 neous. 



The paper in the ' Linnsean Transactions • is accompanied, as 

 is the description in the ' South Downs/ by many figures, the 

 truthfulness of which, as conveying the general characters of 

 outward form, has- never been even approached by any later 

 writer. 



M. Ramond in his f Voyage au Mont Perdu' (before 1815 ; but 

 this is the only case in which I have been unable to obtain ac- 

 cess to the original work) figured the silicified remains of one 

 species and the cast of the same under the two names of Ocel- 

 laria inclusa and Ocellaria nuda, assigning to them characters 

 which a very little study of the nature of flint and of the process 

 of fossilization would have prevented. 



In the first edition of Lamarck's ' Animaux sans Vertebres/ 

 (1816, vol. ii. p. 187), the bodies thus figured and described by 

 Ramond are included. In the second edition of that work (1836) 

 Milne-Edwards expresses doubts (p. 291) of the correctness of the 

 description which had been given of the Ocellaria, but without 

 affording any fresh insight into the real structure of the fossils. 

 In the same edition are included (p. 459) three species of what 

 Goldfuss had previously named Coscinopora, and which is a form 

 of the Ventriculidse. 



William Smith, the " Father of Geology," in his ' Strata Iden- 

 tified' (1816), figures two Ventriculidse in flint (tab. 3. figs. 1 

 and 2), of which the first is a very characteristic figure. He calls 

 them Alcyonia. 



In the l Icones Fossilium Sectiles' of Konig (1820), Ramond's 

 figures are copied (pi. 8. figs. 98 and 99), but without any 

 description. 



In the ' Exposition Methodique des Genres de l'ordre des Po- 

 lypiers ' of Lamouroux (1821) the so-called Ocellaria are also 



