Lect. v.] ORGANIC EOOT-STOCKS. 129 



below and from above, as tliey show ancient or modern 

 relationship. The teeth, of course, are amongst the best 

 of all characters for the use of the taxonomist ; if they 

 do not dominate the creature, they are in harmony 

 with all the rest of its organisation. 



But these superficial, and easily studied, parts are 

 not the whole of the matter ; 1 should be relieved if 

 they were, as my task would then be much easier. If 

 morphology seems obscure, it should be remembered 

 that it has to do Avith the obscure corners of nature. 

 Now the Insectivora are so related to the various 

 orders above them that they are for ever anticipating 

 their diagnostic characters, and they are so related 

 to the types below them that they are constantl}^ 

 seen to retain the marks of those lower forms. They 

 are an exceedingly variable group — promiscuous, so to 

 speak — although in their external adaptive characters 

 they are more uniform than might be supposed. 1 

 speak now both of the teeth and the limbs ; the teeth 

 are of a simple type as compared with what is seen in the 

 higher Eutheria, and the limbs are generally typical as 

 to the number of the digits, which are seldom less than 

 five. Also in the deep, or inner, part of the fore-limbs 

 — the shoulder-girdle — the Insectivora are all typical 

 except one, namely, Potamogale ; having well-developed 

 clavicles ; thus they are capable of using the fore limbs 

 for very various purposes ; the pelvis (liij)-girdle) is 

 not unfrequently open below. 



