AFFINITIES AND GENEALOGY. 153 



Ities between the various classes and orders, with some slight 

 reference to the periods, as far as ascertained, of their suc- 

 cessive appearance on the earth. The Lemuridse stand below 

 and near to the Simiadse, and constitute a very distinct family 

 of the Primates, or, according to Hackel and others, a distinct 

 Order. This group is diversified and broken to an extraordinary 

 degree, and includes many aberrant forms. It has, therefore, 

 probably suffered much extinction. Most of the remnants sur- 

 vive on islands, such as Madagascar and the Malayan archipelago, 

 where they have not been exposed to so severe a competition as 

 they would have been on well-stocked continents. This group 

 likewise presents many gradations, leading, as Huxley remarks,'* 

 "insensibly from the crown and summit of the animal creation 

 "down to creatures from which there is but a step, as it seems, 

 "to the lowest, smallest, and least intelligent of the placental 

 "mammalia." From these various considerations it is probable 

 that the Simiadse were originally developed from the progenitors 

 of the existing Lemuridse; and these in their turn from forms 

 standing very low in the mammalian series. 



The Marsupials stand in many important characters below the 

 placental mammals. They appeared at an earlier geological 

 period, and their range was formerly much more extensive than 

 at present. Hence the Placentata are generally supposed to have 

 been derived from the Implacentata or Marsupials; not, however, 

 from forms closely resembling the existing Marsupials, but from 

 their early progenitors. The Monotremata are plainly allied to 

 the Marsupials, forming a third and still lower division in the 

 great mammalian series. They are represented at the present 

 day solely by the Ornithorhynchus and Echidna; and these two 

 forms may be safely considered as relics of a much larger group 

 representatives of which have been preserved in Australia through 

 some favorable concurrence of circumstances. The Monotremata 

 are eminently interesting, as leading in several important points 

 of structure towards the class of reptiles. 



In attempting to trace the genealogy of the Mammalia, and 

 therefore of man, lower down in the series, we become involved 

 in greater and greater obscurity; but as a most capable judge, 

 Mr. Parker, has remarked, we have good reason to believe, that 

 no true bird or reptile intervenes in the direct line of descent. 

 He who wishes to see what Ingenuity and knowledge can effect, 

 may consult Prof. Hackel's works.^' I will content myself with 



'" 'Man's Place in Nature,' p. 105. 



^ Elaborate tables are given in his 'Generelle Morphologie' (B. ii. 

 s, cliii. and s. 425); and with more especial reference to man in his 

 'Naturliche Schopfungschichte,' 1868. Prof. Huxley, in reviewing 

 this latter work f The Academy,' 1869, p. 42) says, that he considers the 

 phylum or lines of descent of the Vertebrata to be admirably discussed 



