EXTERNAL CHARACTERS OF THE RABBIT. 547 



While Sir William Turner, " the grand master of placental 

 research," in his arrangement of placentas, allots the lowest 

 place to such diffuse forms as that of the pig, passes thence 

 to the cotyledonary of Ruminants, thence to the zonary 

 of Carnivores, and finally to the discoidal of monkeys and 

 man, others maintain that the discoidal, as illustrated in the 

 primitive Insectivora, is the most primitive type. 



To avoid confusion it may be better, as Hubrecht sug- 

 gests, to revert to the old terms caducous and non-caducous, 

 instead of deciduate and indeciduate, for all placental mam- 

 mals have a " decidua," or specially active region of the 

 mucous membrane of the uterus to which the embryo is 

 attached. Moreover, the distinction between deciduate and 

 indeciduate is one of degree, for no sharp line can be 

 drawn between the two types. 



The Rabbit as a type of Mammals. 



The rabbit {Lepus cuniculus) is a familiar representative of 

 the Rodent order, to which rats and mice, voles and beavers, 

 lemmings and marmots also belong. Like the hare {Lepus 

 timidus) and other species of the same genus, and like the 

 Picas or tailless hares {Lagomys), the rabbit has two pairs of 

 incisors in the upper jaw, instead of a single pair. Therefore 

 the genera Lepus and Lagomys are ranked in the sub-order 

 Duplicidentata, in contrast to all other Rodents which are 

 included in the sub-order Simplicidentata. 



With the rabbit's mode of life all are familiar. It is herbi- 

 vorous, and often leaves softer food for the succulent bark of 

 young trees ; it is gregarious and a burrower ; it is very 

 prolific, often breeding four to eight times in a year. It is 

 said to live, in normal conditions, seven or eight years. The 

 rabbit seems to have had its original home in the western 

 Mediterranean region, but it has spread widely throughout 

 Europe, and is now abundant in countries, such as Scotland 

 and Ireland, in which not many years ago it was quite rare. 

 Introduced into Australia and New Zealand it has multiplied 

 exceedingly, and has become a scourge. There are many 

 varieties of rabbit, some in insulated regions illustrating the 

 efiScacy of segregation in fostering divergent types. Thus, 



