26 



tural affinities of the group the polypidom of which is marked 

 by these high characters of structure. 



The difficulty of this task will be readily appreciated when it is 

 considered that it involves an inquiry into the nature, in respect 

 to fossil bodies, of the parts most perishable and most difficult of 

 observation even in recent species, and that it becomes necessary 

 first to remove preconceived notions, and afterwards to begin de 

 novo to find out the true relations. Further than this, in the 

 structure which I have already described, the combined process 

 of induction and direct observation has enabled us to arrive at 

 conclusions which, after the work has once been carefully done, 

 are definite and positive and incapable of being disputed with any 

 show of reason. The present inquiry must depend more entirely 

 upon the process of induction alone, and I cannot but be con- 

 scious that conclusions thus arrived at, however satisfactory to 

 some, will be always more open to dispute. 



Late writers on zoophytes have been in the habit of treating 

 slightingly a reference to the polypidom in determination of ge- 

 nus and species, and of alleging that little or no reliance can be 

 placed upon anything but observation of the polyps themselves. 

 I apprehend, however, that this originates in some misconception. 

 The Mastodon and the Mylodon are creatures which are well 

 realized to the mind, though no part of the softer tissues of either 

 has been ever seen by their describers. In the ' British Fossil 

 Mammals ' are vivified before us hosts of animals, hardly one of 

 which has ever been touched by the hand or seen by the eye of 

 man in other than its harder parts. How is this ? We owe it 

 to the ever-present and strong-felt conviction of the all-prevalence 

 of the Law of Unity, whence their describer would as soon doubt 

 the evidence of his senses as the important truth that there are 

 always present certain constant relations between certain parts. 

 Now either the Law of Unity and the whole principles upon 

 which the British Fossil Mammals have thus been vivified are 

 mere empty words and baseless, or the same principles must apply 

 to every part of the animal kingdom. It would be as reasonable 

 to deny the value of comparative anatomy as applied to fossil 

 mammals because they who first found mammoth bones imme- 

 diately saw in them glorious evidence of the reality of " those 

 days " in which " there were giants on the earth," as it is to treat 

 as of slight value the forms and structure of the polypidoms of 

 zoophytes because Lamouroux and others may have erred in 

 their application of what they saw or thought they saw in them. 

 The cause of the false deductions (they have not been real in- 

 ductions) drawn from observation of polypidoms appears to me 

 very simple. Keeping now to fossil forms and turning over the 

 pages of Goldfuss and others, no one having any knowledge of 



