Lect. II.] SKELETON OF THE PROTOTHERIA. 55 



v,-]iat we find in Serpents and Lizards, wliere they have tlieir cuhnina- 

 tion. 



2. The sl<:ull itself lias a strong and thick foundation of cartilage, 

 the ossification of which forms much of the permanent cranial box, 

 whilst the superficial bones are flat and relatively small, as in such a 

 reptile 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 larvae 

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

 lethra caj)ensis, in whose larval skull a similar vallance of cartilage 

 grows copiously. 



4. The lower jaw is seen, even in the adult, to be the equivalent 

 of the fore part of a Rei^tile's mandible, whilst 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-bone {incus) has not taken on the normal ^Mammalian 

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

 "quadratum" or equivalent of the liinge-segment of the Reptilian 

 mandible. 



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

 columella, or little column, with 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 vertebrae of the spine, as a rule, are devoid of the normal 

 IMammalian bony plates that are added, fore and aft, to the body of 

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

 and agile tyjoes. 



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, cpiite like those of Reptiles and Birds, and there 

 is, as in them, no difi'erentiation or subdivision of the terminal outlet. 



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

 by their skin^ with its hairy covering and its rudimentary milk- 

 glands. Severely apply to them the rule ^^Cucullusnonfacit Monachum" 

 and say — " The skin does not make the Tieast," and liack amongst the 

 Reptiles they would have to be driver.. 



