i

2 - 2

1 - 1

; Pm

5 - 5

; m

3 - 3

=

44.

2 - 2

1 - 1

5 - 5

3 - 3

The central incisors and the lateral lower incisors are very large and pyramidal; and the hind-legs are longer than the fore-legs. Two species are known, one found in south-eastern Russia, the other in the Pyrenees.

Fig. 447.   Skull of the common Hedgehog (Eriuaceus Europaeus).

Fig. 447. - Skull of the common Hedgehog (Eriuaceus Europaeus).

Earn. 4. Erinaceidae. - The fourth family of the Insectivora is that of the Hedgehogs, characterised by the fact that the upper part of the body is covered with prickly spines, the feet are not adapted for digging, and they have the power of rolling themselves into a ball at the approach of danger. The dental formula of the Hedgehog is:

i

3 - 3

; c

0 - 0

; pm

4 - 4

; m

3 - 3

=

36.

3 - 3

0 - 0

2 - 2

3 - 3

The central upper and lower incisors are longer than the others; and the first praemolars are the largest of all the teeth present. The first upper praemolars are sometimes regarded as canines. The common Hedgehog (Erinaceus Europaeus) is in every way a typical example of this family, but is too well known to require any description. Other species of the family are found in North and South Africa and in Asia.

Earn. 5. Centetidae. - The most typical members of this family are the "Tenrecs" (Centetes) of Madagascar. These are small animals resembling the Hedgehogs in appearance and habits, and having the back covered with hair intermixed with fine prickles or spiny bristles, but mostly destitute of the power of rolling themselves into a ball. They have a long proboscislike nose, and the tail is generally rudimentary or absent. The genera Ericulus, Echinops, and Geogale of the island of Madagascar, are allied to Centetes, the last having relationships with the Soricidae. Likewise related to the Tenrecs is the curious genus Solenodon of Cuba and Hayti, in which the nose is very long and pointed, the tail is long and scaly, and the body is covered with coarse fur, without spines. The two central incisors of the lower jaw are small, and are placed between long conical lateral incisors, which are deeply grooved on their inner surfaces. We may also place here the singular Gymnura of Borneo, Sumatra, and the Malay Peninsula. In this genus, the body is covered with long, coarse fur, the tail is long and scaly, the snout is long, and the feet are five-toed.

Fam. 6. Tupaiidae. - The best known members of this family are the "Banxrings" or "Squirrel-shrews" (Tupaia) of India and the Malay Archipelago. These are squirrel-like Insec-tivores, with long bushy tails, the feet plantigrade, five-toed, with naked soles, and sickle-shaped claws. They climb actively amongst the trees, and also run with facility upon the ground. Closely allied to the Tupaiae is the little Ptilocercus of Borneo, in which the tail is very long, and the hairs towards its extremity are arranged like the barbs of a feather.

Fam. 7. Macroscelidae. - This family includes only the little "Elephant-shrews" (Macroscelides) of Southern and Northern Africa. They are readily distinguished by their extraordinarily elongated trunk-like nose, resembling the proboscis of an Elephant, and their very long Kangaroo-like hind-legs.

Fam. 8. Galeopithecidae - This family has been constituted for the reception of a very singular animal which forms a kind of connecting link between the orders of the Insectivora and Quadrumana, having been sometimes placed in the one and sometimes in the other, or having been regarded as the type of a separate order. The family includes only the single genus Galeopithecus, comprising two species of the so-called "Colu-gos" or "Flying Lemurs." The genus is confined to the Indian Archipelago, and the best-known species is the Galeopithecus volans of Malacca, Sumatra, and Borneo. The most characteristic point in this singular animal is the presence of a flying membrane, presenting some superficial resemblance to the patagium of the Bats, but in reality very much the same as the integumentary expansions of the Flying Squirrels and Flying Phalangers. This membrane in the Galeopithecus extends as a broad expansion from the nape of the neck to the arms, from the arms to the hind-legs, and from the hind-legs to the tail, forming an inter-femoral membrane. The fingers are not elongated, and do not support a patagium, as in the Bats, so that the animal has no power of true flight, and can simply take extended leaps from tree to tree. The feet are furnished with five toes each, united by a membrane, but neither the hallux nor the pollex are opposable to the other digits. The dental formula is:

i

2 - 2

c

1 - 1

; pm

2 - 2

; m

3 - 3

=

34.

3 - 3

1 - 1

2 - 2

3 - 3

The upper incisors are separated by a wide central space, and the six lower incisors (fig. 448) are split into narrow strips, like the teeth of a comb. The Galeo-pitheci seem to live chiefly upon fruits, and other vegetable matters. They are nocturnal animals, arboreal in their habits, and they sleep head downwards, suspended by their prehensile tails.

As regards the distribution of the Insectivora in time, the earliest undoubted remains of the order occur in the Miocene, at which period the families of the Talpidae, Soricidae, Erinaceidae, and Centetidae, appear to have been already differentiated. The geological distribution of the order, however, presents no points of special interest.

Fig. 448.   Front of the lower jaw of Galeopithecus volans, showing the form of the incisors. (After Owen.)

Fig. 448. - Front of the lower jaw of Galeopithecus volans, showing the form of the incisors. (After Owen.)