DEVELOrMENT ANP CLASSIFICATION 525 



from the uterus in a condition in which all the parts have 

 oecome fully formed except that it is practically hairless ; 

 the eyelids are at first coherent. As many as eight or ten 

 young are produced at a birth, and the period of i:;es(attoii, 

 i.e., the time elapsing between the fertilization of the ovum 

 and the birth of the young animal is thirty days. Fresh 

 broods may be born once a month throughout a considerable 

 part of the year, and, as the young Rabbit may begin breed- 

 ing at the age of three months, the rate of increase is very 

 rapid. 



The class Mammalia is divided into a number of orders, 

 that to which the Rabbit belongs being called the Rodentia, 

 and also including rats and mice, squirrels, beavers, porcu- 

 pines, and many others. All these are vegetable feeders and 

 are mostly of small size. They possess no canine teeth, 

 and their incisors, which are adapted for gnawing, are never 

 more than two in riumber in the lower jaw, and in most 

 of them there are only two in the upper jaw also. 



PRACTICAL DIRECTIONS 



The specimen used should be over three months old. Place it in a 

 sufficiently large jar or box with a close-fitting lid together with a piece 

 of cotton-wool well soaked in chloroform, arid leave it Until a short time 

 after all movements have ceased. A pair of bone-forceps (p. 12) will 

 be required. 



A. External characters (see pp. 467-470). 



Microscopic preparations of the skin of a Mammal should be examined, 

 and the hairs, and hair-sacs, and sebaceous glands (p. 468) noted. (For 

 mode of preparation, see p. 136). 



B. Skeleton, if more convenient, the detailed examination of the 

 skeleton may be postponed until after the soft parts have been 

 dissected. 



The skeleton of a young rabbit, aboi)t six weeks old, as well as that 



