512 CENTETES AND ITS ALLIES CHAP. 
annoyed. The Tanrec feeds mainly upon earthworms. It is 
“probably the most prolific of all animals,” since as many as 
twenty-one young are said to have been brought forth at a birth. 
Some Opossums, however, have twenty-five teats. 
Hemicentetes' is a genus with two species. These have spines 
mixed with the fur of the back. There is no caecum in this or 
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Fic. 248.—Skull of Tenrec. Centetes ecaudatus. fr, Frontal; max, maxilla ; pa, 
parietal ; p.maz, premaxilla ; sq, squamosal. (After Dobson.) 
in other Centetidae. The teeth are forty in number, there being 
only three molars. 
Ericulus setosus is a small Insectivore, resembling externally — 
a small Hedgehog. It is covered with close-set spines which, 
unlike what is found in Hrinaceus, extend over the short tail. 
The total number of teeth is thirty-six, the formula being 
I2 C+ Pm3 M3. 
Echinops® is another spiny genus which is a stage in advance 
of Ericulus, for still another molar has been lost, reducing the 
total number of teeth to thirty-two. The dental formula is thus 
I2C1Pm3 M3. The zygomata are reduced to mere threads. 
Microgale, a genus recently instituted by Mr. Thomas, is a 
small furry Insectivore with a long tail, which is more than 
double the length of the head and body. There are no less than 
forty-seven vertebrae in the tail, which is relatively longer than 
that of any other mammal. 
Limnogale, discovered by Forsyth Major, is an aquatic genus, 
also furry and not spiny, which has departed from the Cente- 
tid type and taken to an aquatic life. The single species, 
1 Mivart in Proc. Zool. Soc. 1871, p. 58. 
2 Thomas, Proc. Zool. Soc. 1892, p. 500. 
