LECT. I.] DUCKBILL AND ECHIDNA. 3 



The group, class, or family as we may call it which 

 acquired the peculiar faculty of giving of their very sub- 

 stance to their offspring, is as ancient and as venerable 

 as the group of the reptiles, out of which arose the 

 feathered tribes. 



Not out of the stem, however, of the reptilian family 

 tree, but out of its root-stock; and close to that fine 

 sucker, there shot up this other branch, to become the 

 new life-tree of the hairy creatures, that give their young 

 ones suck. Two of the first twigs of that new shoot are 

 still represented by the " Monotremes," namely, the Duck- 

 bill and the Echidna; but, of course, as their line of 

 ancestors must have existed during the formation of the 

 outer half of the earth's ribs, they have had time enough 

 for much specialisation in their structure. Therefore, 

 the scientific imagination, after assuring itself that these 

 living waifs do not lie at the root of mammalian being, 

 bodies forth much lower and more generalised milch-kine 

 than them. 



There are fossil remains, evidently mammalian, from 

 the base of the Secondary rocks. Whether these small 

 jaw-bones belonged to Monotremes that had teeth, or to 

 the more ancient Marsupials, 1 does not affect our argu- 

 ment. Mammalian remains will, I feel sure, turn up 

 some day from older rocks : anyhow, in certain strata 



1 The Monotremes are so called because they have only one common outlet to 

 their body, as in Reptiles and Birds ; Marsupials are so called because they 

 possess a marsupium or pouch. 



