( 9 ) 153 



necessary, but it has been ably discussed by Darwin. 

 The rationale of the " origin of species " as stated by 

 him may be examined a few pages farther on. 



4 

 ft. Of the Characters of Higher Groups. 



a. Relations of Structures. The evidences of deriva- 

 tive origin of the structures defining the groups called 

 genera, and all those of higher grade, are of a very dif- 

 ferent character from those discussed in relation to spe- 

 cific characters ; they are more difficult of observation 

 and explanation. 



Firstly: It would appear to be supposed by many 

 that the creation of organic types was an irregular and 

 capricious process, variously pursued by its Author as 

 regards time and place, and without definite final aim ; 

 and this notwithstanding the wonderful evidences we 

 possess, in the facts of astronomy, chemistry, sound, 

 etc., of His adhesion to harmonious and symmetrical 

 sequences in His modes and plans. 



Such regularity of plan is found to exist in the rela- 

 tions of the great divisions of the animal and vegetable 

 kingdoms as at present existing on the earth. Thus, 

 with animals we have a great class of species which 

 consists of nothing more than masses or cells of proto- 

 plasmic matter, without distinct organs ; or the Pro- 

 tozoa. We have then the Gcelenterata (example, corals,) 

 where the organism is composed of many cells arranged 

 in distinct parts, but where a single very simple system 

 of organs, forming the only internal cavity of the body, 

 does the work of the many systems of the more com- 

 plex animals. Next, the Echinodermata (such as star- 

 fish) present us with a body containing distinct systems 

 i* 



