ORDER INSECTIVORA. 1455 



larthrous Ungulates. The resemblance of the molars of Tupaia to 

 those of the Marsupial genus Perameles, and that between the same 

 teeth in the Creodonts and the Dasyuridce, further suggests the 

 connection of this common stock with the ancestral types of the 

 Polyprotodont Marsupials. 1 The Insectivores agree with the Lemur- 

 oids not only in dental characters, but also in the presence of 

 clavicles, in their plantigrade feet, and the discoidal placenta ; and 

 it is indeed quite evident that the ancestral stock of the Primates 

 must have been provided with complete clavicles. 



This order may be divided into the suborders Insectivora Vera 

 and Dermoptera. The former may be further subdivided into two 

 sections, in the first of which the molars have broad and squared 

 crowns, with their cusps frequently arranged like the letter W, while 

 in the second section the crowns of these teeth are narrow and 

 V-shaped, with the apex of the V directed inwardly (tritubercular). 

 The Dermoptera, represented only by the volant genus Galeopi- 

 thecus, are unknown in a fossil condition. It should, however, be 

 observed that this genus, although not on the direct line of descent, 

 indicates the manner in which the Insectivores have become modi- 

 fied into the Bats. The first section of the Insectivora Vera 

 comprises the existing Tupaiidce, Macrosceiididce, Erinaceidce, So- 

 ricidce, and Talpidce, together with the extinct Microchosridce and 

 Dimylidce. 



Family Tupaiid.l. — The Tupaias are small arboreal Insectivores 

 confined at the present day to the Indo-Malayan region. The 

 genus Parasorex, from the Middle Miocene of the Continent, has 



the dental formula 7. , C. - , Pm. -, M. -, and may be provision- 



3 i 4 3 



ally placed in this family, although, according to Dr Schlosser, it 

 approximates in several respects to the Macroscelididce. There is 

 one more upper incisor and one more premolar in each jaw than in 

 Tupaia, and the last two premolars are somewhat more complex. 

 The above-mentioned writer regards this genus as the representative 

 of a group connecting the Tupaiidce of Asia with the Macroscelididce 

 of Africa. An Insectivore from the Middle Miocene of Sansan, 

 described as Lantanotherium, is said to be very nearly allied to 

 Tupaia. 



Family Erixaceid^e. — Since the Macroscelididce are at present 

 unknown in a fossil state, we may pass to the Erinaceidce or Hedge- 

 hogs. In the typical genus Eri?iaceus (fig. 1339) the dental formula 



is I. -, C. -, Pm. , M. - ; the first pair of upper incisors are large, 

 21 23 



1 On embryological grounds some authorities are disposed to regard the Mar- 

 supials as being off the line of Eutherian ancestry ; but it must be borne in mind 

 that the evidence only includes existing types. 



