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VERTEBRATA. 



Order VI. INSECTIVOEA. 



Plantigrade. Three kinds of teeth ; incisors short, simple. 

 Five toes, furnished with claws. Clavicles present. 



The canine teeth are small and the molars are studded with 

 small tubercles, fitting them more for grinding than for tearing 

 their food. The limbs are short and feeble, except in the Macro- 

 scelidse &c. The mammae are abdominal. The placenta is deci- 

 duate and discoidal. The brain is without convolutions. A gall- 

 bladder is always present. 



In the mole the eye is very small and nearly covered by the 

 skin ; but in the embryo it is as well developed as usual. The 

 hedgehog has a powerful cutaneous muscle attached to the inte- 

 gument, by which it is enabled to roll itself into a ball or to 

 erect its spines. This power is not possessed by its allies. In 

 the Soricidae the lower incisors become anchylosed to the jaw- 

 bone, a reptilian character not occurring in any other mammal. 



The Insectivora are mostly nocturnal and subterranean, and 

 many hibernate. The Tupaiidae are arboreal, and live on fruit 

 as well as on insects. A few are aquatic or semiaquatic. 



In this order we have the hedgehog (Erinaceus europ&us), two 

 species of shrews generally confounded together, both common 

 (S&rex tetragonurus and Sorex rustious), [Crocidura aranea has 

 not been found in England], water-shrew ( Crossopiis fodiens), and 

 mole (Talpa europcea). Galeopithecus is placed here by Huxley, 

 but by Glaus and Schmarda it is retained among the lemurs. 

 With some of the characters of the latter, it has also a tegumentary 

 membrane extending from the neck to the tail, and embracing 

 the legs. 



