Lect. II.] ANCESTORS OF THE MAMMALIA. 47 



much as, or more than, the skull of the Ornitho- 

 rhynchus differs from that of a Man. 



We may suppose the ancestors of the original teatless 

 mammals (Prototheria) to have been something like, and 

 not much higher than, the larva of the nailed Toad, and 

 that these underwent an amount of transformation, 

 during an active out-of-door life, equal to that under- 

 gone by the existing type. Afterwards, by little and 

 little, such Prototheria may have improved themselves 

 into higher and still higher types ; they have had plenty 

 of time for such changes. 



ADDENDUM TO LECTUEE II. 



Bibliography: Eefbrences to Works and Papers treating 

 OP THE Ornithorhynchus and Echidna. 



Armit, Captain William E., F.L.S., "Notes on the Presence of 



Tachyglossus and Ornithorhynchus in JSTorthem and North 



Eastern Queensland," Proceedings of the Linnean Society,. 



Zoology, vol. xiv., 1879, pp. 411-413. 

 Bennett, Dr George, F.L.S., F.Z.S., &o., Gatherings of a Naturalist 



in Australia. London: John Van Voorst. 1860. 

 Flower, Prof. W. H., LL.D., F.E.S., An Introduction to the 



Osteology of the Mammalia. London : MacmiUan & Co. 1876. 

 Article " Mammalia " in the Encyclopoedia Britannica, 9th 



edit., vol. XV., pp. 377-378. 

 Huxley, Prof. T. H., LL.D., Pres. E.S., A Manual of the Anatomy 



of the Vertebrated Animals, pp. 319-323. London: J. & A. 



ChurchiU. 1871. 



