Zöology; a textbook for colleges and universities . of Australia and New Guinea. The egg-layinghabit of the duckbill may be directly traced to its. Photograph by E. R. Sanborn, N. Y. Zool. 169. Echidna (Echidna aculcata). reptilian ancestry, but the peculiar ducklike muzzle,suggesting a bird or a duck-billed dinosaur, is evidentlya special adaptation. The teeth are absent in the adult,but present at an early stage; so the animal has evi-dently had toothed ancestors. The spiny anteatersare entirely different in appearance, having strongspines plentifully mixed with the fur, and the sku
Zöology; a textbook for colleges and universities . of Australia and New Guinea. The egg-layinghabit of the duckbill may be directly traced to its. Photograph by E. R. Sanborn, N. Y. Zool. 169. Echidna (Echidna aculcata). reptilian ancestry, but the peculiar ducklike muzzle,suggesting a bird or a duck-billed dinosaur, is evidentlya special adaptation. The teeth are absent in the adult,but present at an early stage; so the animal has evi-dently had toothed ancestors. The spiny anteatersare entirely different in appearance, having strongspines plentifully mixed with the fur, and the skullproduced into a long, slender beak, very suggestive ofa weevil. 3. The Eutheria-are divided into the Marsupial and Marsupials;Placental mammals. The marsupials are in some degree gar00anintermediate between the Prototheria and the placen- opossum, m, . ,. and their tals. The young are born in a very rudimentary con- relativesdition, and are not nourished by a typical placenta orbase of attachment to the mother. These little-de-veloped young are nearly always concealed in a pouch ormarsupium, where they are fed with the parents milk. 398 ZO
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectzoology, bookyear1920
