Explanation:

Difference # Prototheria:

1. Eggs or Young ones :

Oviparous

2. Mammary:

Mammary glands are without nip­ples or teats.

3. Glands:

Indistinct or absent.

4. Pinna:

Present and is formed by the nasal and premaxilla bones.

5. Beak Cloaca or ANUS:

Cloaca

6. Teeth:

Absent, only temporary molar milk teeth present in Ornithorhynchus which disappear in adult state. Tachyglossus lacks teeth in any stage of development.

7. Position of testes:

Abdominal.

8. Ureters:

The ureters open into a urinogenital sinus, not open into the urinary blad­der.

9. Pectoral GIRDLE:

(a) With a large coracoid

(b) Scapula without spine

10. Interclavicle:

T-shaped interclavicle

11. Fully homeothermic or not:

EXAMPLE:

Platypus (Ornithorhynchus sp.)

Echidna (Tachyglossus sp.)

Pro-echidna (Zaglossus sp.)

Difference # Theria:

1. Eggs or Young ones:

Viviparous

2. Mammary glands:

Mammary glands with nipples or teats.

3. Pinna:

GENERALLY present (absent in aquatic mammals).

4. Beak:

Mammary glands with nipples or teats.

5. Cloaca or anus:

All therians possess anus expected pikas (pika), a lagomorph type.

6. Teeth:

Present except scaly ant-eater (Man is sp.) and Baleen whales etc.

7. Position of testes:

Generally within the scrotal sacs.

8. Ureters:

The ureters open directly into the urinary bladder.

(a) Coracoid small

(b) Scapula with a spine

9. Pectoral girdle:

(a) Coracoid small

(b) Scapula with a spine

10. Interclavicle:

Absent

11. Fully homeothermic or not:

Fully homeothermic

Example:

Kangaroo (Macropus giganteus)