640 INSECTIVORA 
has four digits, of which the two outer are small, while the middle 
ones are large, with immensely powerful claws. 
Extinct Types.—The only fossil forms which can be referred to 
the section of the Insectivora with tritubercular molars are the 
Leptictide, of the Eocene and Miocene of North America. This 
family includes the genera Leptictis, MJesodectes, and Ictops, all of 
which are regarded by Dr. Schlosser as true Insectivora, although 
they were placed by Professor Cope with the Creodont Carnivora. 
Bibliography of Insectivora.—Peters, Reise nach Mossambique—Sdugeth. 1852; 
Id. ‘“‘Ueber die Classification der Insectivora,” JJonatsh. Akad. Wissensch. 
Berlin, 1865, and other papers; Mivart, ‘‘On the Osteology of Insectivora,” 
Journ. Anat. and Phys. 1867, 1868, and Proc. Zool. Soc. 1871; Gill, ‘Synopsis of 
Insectivorous Mammals,” Bull. Geal. and Geog. Survey, U.S.A. Washington, 
1875 (includes a general bibliography of the order) ; Dobson, Monograph of the 
Insectivora, Systematic and Anatomical, London, 1882-90. 
