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along with that part of the uterine wall to which they 

 become firmly attached, constitute the true (allantoic) 

 placenta, connecting the embryo with the mother. 



Gestation (pregnancy) period long ; except in Marsupials, 

 which have a rudimentary allantoic placenta and a well- 

 developed yolk-sac placenta. After birth the young are 

 suckled (milk nutrition) by the mother for a variable period. 



Characteristic features are printed in italics. 



* Except Monotremes. 



f Except Monotremes and Marsupials. 



State the Number and Different Kinds of Teeth in a Typical 

 Mammalian Dentition. Give the Dentition of the 

 RabUt. 



Forty-four teeth (permanent set), eleven on each side of 

 upper and lower jaw. The front ones (on premaxillae) 

 are the incisors, for seizing and cutting ; behind these (on 

 the maxillae) are the canines, followed by premolars and 

 molars, which are adapted for grinding and crushing. 

 Incisors and canines generally have single roots, the grinders 

 have two or more roots. Since the number of teeth on each 

 side is the same, the formula expressing this dentition 

 would be : 



The form of the teeth is according to the nature of the 

 food. When the crown has a number of cusps, the tooth 

 is termed bunodont ; when the cusps form a single (cutting) 

 ridge, secodont ; when the cusps are not conical but modified 

 as partly longitudinal partly transverse crescents, seleno- 

 dont, or forming transverse ridges, lophodont. The denti- 



2033 

 tion of the Rabbit is = 5 it is without canines. 



The Rabbit (Lepus), 

 A Type of Mammals, 



Write Short Explanatory Notes on the following : Diastema, 

 Perineal Glands, Panniculus carnosus, Panniculus 

 adiposus. 



The diastema is a gap at each side of the mouth, between 

 the front and back teeth ; it is overlapped by the hairy 

 lips which there extend into the mouth cavity. 



