PREFACE. 



Zoology Those of the specimens, according to the 

 principles of Mineralogy and Geology. 



It is particularly necessary to distinguish, by 

 description, the essential form of the reliquium from 

 the accidental that is, the form of the original 

 body, from that which has arisen in the fossil from 

 the mode of mineralization, the constituent sub- 

 stance, and the soil of the specimen./ Hence, the 

 use of the present principle will be sufficiently ap- 

 parent (/). 



8. The nomenclature of reliquia should always 

 manifest the extent of our knowledge with respect to 

 the original bodies. 



On this principle, if we know the original 

 recent species, the name of the reliquium must dis- 

 tinguish it. If only the kind or genus, still that 

 kind must be nominally pointed out in the fossil. 

 In temporary species of reliquia ( v. p. 194.) the part 



( / ) It will be advisable for the student never to make his 

 descriptions from single examples, however perfect they may 

 appear to be. In many instances, it is only by collating a num- 

 ber of specimens, that we are able to acquire that knowledge of 

 a species, which is sufficient for the purpose of its discrimination* 



