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pouch is often developed which may become a median vagina (three 

 vaginae). A yolk-sac placenta, functional as such ; the allantoic 

 placenta, when present (e.g., Perameles), is small. Gestation period 

 short ; young, born prematurely and unable to suck, are nursed 

 in the pouch or marsupium (on lower part of abdomen), and the 

 mother, by compressing her belly muscles, forces the milk through 

 her (temporary) teats into their throats. 



Write short Notes on the following Marsupials, stating Special Features 

 and Distribution : Didelphys, Thylacinus, Myrmecobius, 

 Notoryctes, Perameles, Tarsipes, Macropus. 



Didelphys (Opossum). Arboreal. Tail prehensile. Pouch gener- 

 ally absent. Dentition, 5134 . N. and S. America. 



Thylacinus (Tasmanian Wolf). Dog-like. Carnivorous (canines 



large.) ?* 

 3134 



MyrmecobiuS (Banded Ant-eater). Squirrel-like. Long extensile 



tongue. Without a pouch. Dentition f/ }' ^' f or f = the largest 



3, 1, o, 5 or o 



number of teeth known in any heterodont mammal. 



Notoryctes (Marsupial " Mole "). Burrowing and mole-like ; a 

 good example of " convergence " (i.e., forms not related, yet ex- 

 hibiting similar characters acquired through similar habits). Desert? 

 of S. Australia. 



Perameles (Bandicoot)., Burrowing. Insectivorous. An allantoic 

 placenta. Australia, Tasmania, New Guinea. 



Tarsipes. Angle of mandible not inflected. Australasia. 



Macrppus (Kangaroo). Herbivorous. Tail long, and used for 

 supporting body. Hind limbs long, adapted for leaping. Foot has 

 four digits ; hallux absent, second and third toes slender and bound 

 together by integument (syndactylous), fourth toe very large. 



Dentition 3> or l ' *' 4 . Australia, Tasmania, New Guinea. 

 1, 0, 2, 4 



Sub Class Eutheria. 



Briefly state the Chief Distinctive Features of the Eutheria. 



Small anterior commissure ; large corpus oallosum. Anus and 

 urinogenital opening separate. The vaginae fused as one. A true 

 (allantoic) placenta, deciduate or non-deciduate (i.e., the maternal 

 part of placenta does not come away at birth, because the ectoplacenta 

 is not inseparably fused with the uterine placental lobes). A pro- 



