286 



The Museum Gazette 



" He is in a low state of mental development who is 

 unaware of the extreme antiquity of the planet on which we 

 dwell ; and it is a far cry backwards to the time when the 

 young of four-footed beasts first tasted milk. The group, class, 

 or family — as we may call it — which acquired the peculiar 

 faculty of giving of their very substance 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, how- 

 ever, of the reptilian family tree, but out of its root-stock ; and 

 close to that 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 Duckbill 

 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, does not affect our argument. Mamma- 

 lian remains will, I feel sure, turn up some day from older 

 rocks ; anyhow, in certain strata of the secondary epoch we 

 get various remains of the group above the Monotremes — 

 the Marsupials. Professor Huxley's classification of the 

 mammals is as follows : — 



" (i) Prototheria, or the Monotremes ; examples — Duckbill 

 and Echidna. 



" These are the lowest mammals known ; they have udders, 

 or milk glands, but no teats, and in many things stand on the 

 same level as the Sauropsida (reptiles and birds). 



"(2) Metatheria, or the Marsupials; examples— opossum, 

 phalanger, kangaroo. These have, besides the milk glands, 



