616 INSECTIVORA 
line of descent. The deeply pectinated crowns of the lower incisors 
of Galcopithecus are quite unique in the class, and the only approach 
to the double-rooted canine, except in Hrinaceus and Talpa, is found 
among the Marsupials in Perameles, where the root of the canine is 
grooved. 
Suborder INSECTIVORA VERA. 
Upper and lower incisors conical, unicuspidate or with basal 
cusps only, the lower not pectinated ; limbs free, formed for 
terrestrial progression. : 
The following table gives a key to the distinctive characters of 
the existing families :— 
I. Upper molars broad, multicuspidate, with more or less well-defined 
W-shaped crowns. 
A. Symphysis pubis long ; generally a caecum ; cerebral cavity 
comparatively large. 
a, Orbit encircled by bone ; metatarsus moderate ; arboreal. 
Tupaude. 
b. Orbit not encircled by bone ; metatarsus greatly elongated ; 
terrestrial. Macroscelidide. 
B. Symphysis pubis short or none; no cacum ; cerebral cavity 
small ; skull without postorbital processes. 
a, First and second upper molars with a central fifth cusp. 
a’. Tympanic annular, not forming a bulla. Erinaceide. 
b. No central fifth cusp to upper molars. 
a’. Tympanic annular, not forming a bulla; no zygomatic 
arch. Soricide. 
b’. Tympanic forming a bulla; zygomatic arch developed. 
Talpide. 
Il. Upper molars narrow, with V-shaped crowns. 
a. Tympanic annular, not forming a bulla; zygomatic arch 
imperfect. 
a’, No clavicles. Potamogalide. 
b”. Clavicles well developed. 
a”. Skull constricted between the orbits; penis sus- 
pended. Solenodontide. 
b”. Skull not constricted ; penis pendent, retractile. 
Centetide. 
¥. Tympanic forming a bulla ; zygomatic arch well developed. 
Chrysochloride. 
The second section, in which the molars are of the primitive 
tritubercular type, should probably be regarded as containing the 
most generalised representatives of the order ; and it is noteworthy 
that the whole of them are confined to Africa, Madagascar, and 
the West Indies, whereas most of the first section are widely 
distributed over the Palzarctic and Oriental regions. None of the 
