MONOTREMATA. 
59 
the Golden Moles [Chnjsochloris) (See woodcut_, p. 25)^ the third 
and fourth digits bearing large digging claws, while those of the 
other three are small and slender. 
Order XII. MONOTREMATA. 
(Case 98.) 
The Order Monotremata, like the Marsupialia, represents by 
itself one of the primary sections or subclasses into which the 
Mammals are divided. In all their anatomical characters these 
animals show a remarkably low type of organization, a type trans- 
mitted more or less directly from some of the earliest Mammalian 
forms. 
Fig. 24. 
Echidna acideata. 
The Monotremes lay eggs and have pouches, but their mode of 
incubation is not yet satisfactorily known ; they are without true 
mammary nipples, the mother’s milk exuding from groups of pores in 
the skin. The males are provided with remarkable horny spurs on 
their heels, connected with a small gland on the back of the thigh, 
the function of which is entirely unknown. The temperature of 
the blood is lower than that of other mammals, recent observations 
having shown that that of Echidna stands only at about 78°, 
some 20° lower than that of man, and about 30° below that of 
the average of birds. 
The few living species of Monotremata are referred to two 
families, the first being the Echidnidcc, characterized by the long 
