CHAP. XVI THE HEDGEHOG FAMILY 509 
There is, furthermore, a distinct tendency towards a dis- 
appearance of functional milk teeth, which is best seen in 
Sorex, where there are only seven milk teeth, none of which ever 
cut the gum. This suppression of the milk dentition is like that 
of the Marsupials, Edentates, and Whales, all of which appear to 
be—the first certainly are—ancient forms of mammalian life. 
There is also a fairly well-defined, though shallow, cloaca in 
many genera. Finally, the testes are purely abdominal in some, 
and in none is there a full descent into a scrotum, as in the more 
highly-developed Eutheria. 
SuB-OrDER 1. INSECTIVORA VERA. 
Fam. 1. Erinaceidae.—This family contains ‘the genera 
Erinaceus, Hylomys, and Gymnura. 
Hylomys, considered by Dobson to fall within Gymnura, is 
kept separate by Leche. 7. swillus is a Malayan animal, small in 
size, about 5 inches long, with a short tail. Like Gymnura it is 
spineless. The ears are decidedly large and nude. There is one 
pair of inguinal and one pair of thoracic teats. The colour 
above is a rusty brown with yellowish-white under parts. The 
palms and soles are quite naked. In its general form it recalls 
Tupaia very much more than its own immediate relatives. 
There is no doubt, however, of its systematic position when the 
skeleton and teeth are examined. A variety has been described 
from altitudes of 3000 to 8000 feet on Mount Kina Balu in Borneo. 
It has the complete dentition of forty-four teeth. There are 
fourteen pairs of ribs. As in Gymnura the tibia and fibula are 
united below. The genus is considered by Leche to be the oldest 
existing type of Erinaceidae. 
fymnura” is also a Malayan form with the complete dentition 
of the last, but with fifteen pairs of ribs and a longer tail, con- 
sisting of twenty-three vertebrae as against fourteen. There is, 
as with Hylomys, but one species, G@. raffesii. This animal has 
a peculiar odour, resembling decomposed cooked vegetables. 
1 “Bemerkungen iiber die Genealogie der Erinaceen.” In Festschrift (/f. 
Liljeborg, 1896. See also Anderson, Trans. Zool. Soc. viii. 1874, p. 453. 
2 Dobson, ‘‘ Notes on the Anatomy of the Erinaceidae,” Proc. Zool. Soc. 1881, 
p. 389. 
