43^ KOSS-— ON EVOLUTION. 



are almost unknown, although the researches of the ** Challenger" 

 Expedition has shewn that they are abundant, and as the nature of 

 their habitat must effectually prevent the rapid ingress of later, 

 more highly differentiated, and more typical forms, that is, forms 

 typical of a larger group, they will be found to be more synthetic, 

 and antique in their more general characteristics, such as those 

 pertaining to Order and Family, but at the same time more differ- 

 entiated iu their more specific characteristics, such as those pertain- 

 ing to Genera and Species, as was found to be the case with those 

 already discovered. The wonderful development of the organs of 

 vision of the more predatory and active Types and their atrophy in 

 the case of the others, is a striking illustration of the possibilities of 

 differentiation in adaptation to circumstances, though paralleled by 

 the differentiation of the imperfectly sighted types of earlier times 

 into the (usually) better sighted, higher, and more active Types of 

 the present day on the one hand, and into the sightless sessile Types 

 on the other. Any attempt to estimate the numbers of extinct 

 Species must necessarily be very vague from the necessary imper- 

 fection of the Geological Record, as well as our as yet imperfect 

 acquaintance with it ; but enough is known to make it certain that 

 the extinct Species were many times more numerous than those 

 now existing, so that it is clear that many millions of Species have 

 been created, during a period of millions of years ; and this was all 

 accomplished in the most gradual and systematic manner possible, 

 both as to creation and extinction ; the apparent exceptions occurring 

 in exceptional circumstances, and themselves conforming to their 

 appropriate laws, and being therefore of that kind which have been 

 said to *' prove the rule." It is not therefore surprising that while 

 all, who have any considerable knowledge of the subject, are Evolu- 

 tionists in the sense of comprehending that creation of the successive 

 types exhibit^the gradual evolution or unfolding of certain ideas, 

 a very large majority of the leading Men of Science of the present 

 day believe that the Creator formed the various Species, so called, 

 by the operation of His Laws from a single protoplasmic prim- 

 ordial Type, rather than by a direct, miraculous (in the ordinary 

 sense of that word) creation of as I have said of many millions of 

 Species spread over many millions of years, and governed in the 



