of the Chalk. 87 



plain, we should find the places of the fibres indicated by hollow 

 tubes disposed through the mass. Of course the presence of 

 great pressure, or the percolation of water or other causes, will 

 have frequently destroyed every trace of the animal, or partially 

 destroyed it, leaving perhaps a mere iron-mould to mark its 

 place ; if the fibre were dead, not even that. I am fortunate in 

 having some very beautiful specimens of the dead fibre tubes in 

 my possession, — specimens which naturally escape ordinary at- 

 tention, there being no colour to attract the eye, and the aid of 

 the microscope being necessary to detect the facts. 



In my notes I find several other points examined, but the 

 space to which I am necessarily restricted prevents my entering 

 into further detail here, and I think that I may rely on the can- 

 dour of every competent observer, that, having thus far touched 

 on material points, others which may occur to him have not 

 escaped my attention. Proceed we now to the results of these 

 observations. 



I propose to point out, first, some of the general and most im- 

 portant characters connected with the external form of the body 

 of the living animal ; second, the same of the roots ; third, to 

 show what is the intimate structure of both ; and lastly, to en- 

 deavour to indicate the natural affinities of the whole group. 

 And though it is impossible for me to do otherwise than pain- 

 fully feel that the attempt is vain to convey, by a few words and 

 figures, that certainty of conclusion which I have derived from 

 such very extended observation, I will hope to impart some con- 

 sciousness of a reality. 



Every reader familiar with the human brain is aware that it 

 consists of a very extensive surface folded up in numerous con- 

 volutions in order to pack it in the small compass of the skull, 

 just as for convenience the pocket-handkerchief is doubled up 

 to put it in the pocket. The re- 

 markable resemblance between the Fl 'g- 

 annexed section of a Ventriculite C 

 (in flint) in my possession, and 

 any cross section of the cerebellum 

 cannot fail to strike every reader, — 

 a resemblance arising from the 

 simple circumstance that both 

 are examples of a similar mode 

 adopted by nature for packing an extensive surface in a small 

 space*. But no one will pretend to assert that those ridges, of 

 which the outline is seen in the section of the cerebellum, are 

 " cylindrical fibres ;" nor will any one infer a power of expansion 



* Plates 63 B, 64, 64 A, and 64 B of Prof. Owen's « Odontography ' afford 

 striking illustrations of the application of the same contrivance to the hard- 

 est, as in the brain it is applied to one of the softest, of organic tismtes; 



