Lect. II.] RELATION OP MAMMALS TO REPTILES. 51 



gi'oup. Of course, the scaly covering is mimetic of the Lizard's 

 scales, and is in reality made up of cemented hairs; that may 

 pass ; but not the structure of the sternum in some species, with 

 its long 'xiphisternal horns,' as in the StelUonidce, and the 

 cartilaginous abdominal ribs, as in the Chameleons, and some other 

 kinds."! In the poverty of the existing, but highly modified, Proto- 

 theria, we are glad to get any addition to our materials for work, any 

 knowledge that may help us in our deductions. As I shall soon 

 show, the Edentata are only a sort of Eutheria, or high kind of 

 mammal, quoad hoc, in this and that point in their organisa- 

 tion; in other respects they have kept in a low estate, having 

 the slow temper of some races of men, who are haters of change, 

 however beneficial, and of whom it may be said " as their fathers 

 did, so do they." 



My task in writing of these types, after straining the eyes of my 

 mind to see what sort of folk those mammalian forefathers were, is 

 rendered more difficult through my being precluded the free use of 

 technical terms. A rustic gymnast in a sack, with nothing but his 

 homely features free, and yet having the necessity of jumping laid 

 upon him, is not more an object of sympathy than a biologist, 

 when robbed of his familiar terms — his special nomenclature. 

 As the movements of the one are of necessity a series of jerks, so 

 the thoughts of the other are too often put into language that to an 

 easy-going, well-trained writer must seem to be spasmodic. Loosen- 

 ing my bonds a little, however, and taking a few technical liberties 

 with the reader, I will endeavour to give some of the remarkable 

 evidences to be found in the quasi reptilian nature of these prim- 

 ordial beasts. In the mid-region of the Vertebrata, especially 

 amongst the Serpents and Lizards, we come across some very remark- 

 able structures in the fore part of the organs of smell ; these are 

 called " Jacobson's organs." They were described by Eathke, in the 

 Snake, under the term "nasal glands"; that term was adopted by me 

 in my papers on the Skull of the Snake and of the Lizard.^ In those 

 papers the contained organ was not described, as not being in my plan, 



1 See my memoir on the "Shoulder-Girdle and Sternum,'' Eay SodeUj 

 Publications, 1868, plate xxii. fig. 13. 



^Philosophical Transactions, 1878, plates xxvii.-xxxiii., and 1879, plates 

 xxxvii.-xlv. 



