. Outlines of zoology. totheria {Syn. Ornithodelphia),Orders Monotremata and (?) AUotheria The Monotremes include the duckmole {Ornithorhynchusanatinus), the spiny ant-eater {Echidna aculeata), and athird form resembling Echidna, but often referred to adistinct genus as Proechidna. These are the lowestMammals, very different from all the rest, and they exhibitaffinities with Reptiles. The duckmole is found in the rivers of Australia andTasmania; Echidna in Australia, Tasmania, and New Guinea; Proechidna in NewGuinea. In Ornithorhynchus the skinis covered with soft fur; inEchidna and Proechidna

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. Outlines of zoology. totheria {Syn. Ornithodelphia),Orders Monotremata and (?) AUotheria The Monotremes include the duckmole {Ornithorhynchusanatinus), the spiny ant-eater {Echidna aculeata), and athird form resembling Echidna, but often referred to adistinct genus as Proechidna. These are the lowestMammals, very different from all the rest, and they exhibitaffinities with Reptiles. The duckmole is found in the rivers of Australia andTasmania; Echidna in Australia, Tasmania, and New Guinea; Proechidna in NewGuinea. In Ornithorhynchus the skinis covered with soft fur; inEchidna and Proechidna Stock Photo
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. Outlines of zoology. totheria {Syn. Ornithodelphia),Orders Monotremata and (?) AUotheria The Monotremes include the duckmole {Ornithorhynchusanatinus), the spiny ant-eater {Echidna aculeata), and athird form resembling Echidna, but often referred to adistinct genus as Proechidna. These are the lowestMammals, very different from all the rest, and they exhibitaffinities with Reptiles. The duckmole is found in the rivers of Australia andTasmania; Echidna in Australia, Tasmania, and New Guinea; Proechidna in NewGuinea. In Ornithorhynchus the skinis covered with soft fur; inEchidna and Proechidna
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Image ID: 2AGBGCF
. Outlines of zoology. totheria {Syn. Ornithodelphia),Orders Monotremata and (?) AUotheria The Monotremes include the duckmole {Ornithorhynchusanatinus), the spiny ant-eater {Echidna aculeata), and athird form resembling Echidna, but often referred to adistinct genus as Proechidna. These are the lowestMammals, very different from all the rest, and they exhibitaffinities with Reptiles. The duckmole is found in the rivers of Australia andTasmania; Echidna in Australia, Tasmania, and New Guinea; Proechidna in NewGuinea. In Ornithorhynchus the skinis covered with soft fur; inEchidna and Proechidna thereare spines among the hairs.The mammary glands in thefemale Ornithorhynchus openon a fiat patch; in Echidna,in a depressed area aroundwhich a temporary pouch seemsto be developed. There areno distinct mammae. The vertebral centra haveweak epiphyses in Ornithorhyn-chus, and apparently none inEchidna. In the duckmole thepost-sacral vertebrae are strongerThe skull is smooth and polished as inThe rami of the lower jaw. Fig. 402.—Pectoral girdleof Echidna. c., Scapula; £?/., clavicle; i.cl.presternum or interclavicle \co.coracoid or metacoracoid: e.co.procoracoid or precoracoid ; st.mesosternum. than the pre-sacral.Birds, for the sutures disappear. do not unite in front, have no ascending process, and have aslightly inflected angle. In Ornithorhynchus there are truemammalian teeth, but only in the young; in Echidjia noneare present. Cervical ribs remain distinct for a time at least;the odontoid process of the second vertebra is for a longtime free from the centrum. Except on the atlas ofEchidna, the cervical vertebrae are without zygapophysesor articular processes. The (meta-) coracoids reach thesternum; there are also large precoracoids (often calledepicoracoids, but homologous with the precoracoids of many SUB-CLASSES OF MAMMALS. 741 S2 S g z S M fc; o || o rt Oi .ti S 3 ^M .S .2 1!» -S S I i % |e sII W 1=! Sm^ e-r; ft O r c o rt i m ft ri ElO„ ?5 Sds; ri o ^ G 2 = 4) 0