Lkct. II.] SKELP:T0N of the PilOTOTHERIA. 55 



A\liat we find in Serpents and Lizards, where tliey have their cuhuina- 

 tion. 



2. The skull itself has a strong and thick foinidation of cartilage, 

 the ossihcatiou of which forms much of the permanent cranial 1:)0X, 

 Avhilst the superhcial hones arc flat and relatively small, as in such a 

 rcjitile as the Lizard. 



3. The fore face has a large vallance of solid cartilage, such as 

 is not seen again, until we get down to the most archaic of the larviB 

 seen in any metamorphosing type whatever — for example, in Dadij- 

 letltra capmsis, in whose larval sJiuJI a similar vallance of cartilage 

 groAvs copiously. 



4. The lower jaAV is seen, even in the adult, to he the equivalent 

 of the fore })art of a Eeptile's mandihle, wdiilst the malleus (hammer- 

 bone) is manifestly the hinder part of such a mandible, and has, 

 cemented to it, a most rudimentary ear-drum bone. 



5. The anvil-l)one (incus) has not taken on the normal Mammalian 

 form, but is a mere flat segment of ossified cartilage ; it is a very small 

 " quacbatum " or e(]uivalent of the liinrie-serjment of the Reptilian 

 mandible. 



6. The stapes (stirrup-bone) is not normal, it is merely a Reptilian 

 colmneJla, or little column, Avith a dilated upper end. 



7. The shoulder-girdle is perfect, both in its complete moieties of 

 ossified cartilage, and in its superadded triple clavicular plates of simple 

 ossified membrane. 



8. The vertebrffi of the spine, as a rule, are devoid of the normal 

 ]\[ammalian bony plates that are added, fore and aft, to the body of 

 each vertebra, to take off the shock in the quick movements of high 

 and agile types. 



9. The hip-girdle repeats the so-called " pre-pubic " bars seen in 

 Salamanders and in some kinds of Skate. 



10. The organs for the growth and maturation of the germs 

 are, in essentials, c[uite like those of Reptiles and Birds, and there 

 is, as in them, no differentiation or sulxlivision of the terminal outlet. 



So that these creatures are just plucked out of the Reptilian group 

 by their ski7i, with its hairy covering and its rudinrentary milk- 

 glands. Severely apply to them the rule "Cucullns?io7ifacif Monackum" 

 and say — "The skin does not make the beast," and Ixack amongst the 

 Reptiles they Avould have to be drive]!. 



