MEANING OF JAGUAR AND LEOPARD ROSETTES 121 



animal with a GlyptodonA?/^ carapace. - I repeat that the bone- 

 plate rosettes on Figs. 61 and 62 speak to us only too plainly. 

 These armour-plates of extinct animals are to my mind the ' blocks ' 

 which gave the Jaguar skin the impressions of the groups of spots 

 or rosettes, much modified in subsequent innumerable generations. 

 In other words, the skin, on losing its hard calcareous plates, retained 

 somehow an impression of them, which modified the pigmentation, 

 where the plates in its ancestors originally stood. Or again, to put it 

 more ' nervously,' the action of the nerve-centres which caused the 

 deposition of calcareous matter in rosette-form, on the skin of the 

 Glyptodonts, continued to act when there was an insufficient amount 

 of calcareous matter in the blood for this purposed That is, in the 

 nerve-centres a sort of memory of former plates remained, which 

 expressed itself in pigments after the calcareous carapace had gone. 

 This nervous action then resulted in the deposition of pigments of 

 colours different from those of the general skin. In many mammals 

 this nervous action dwindled into the deposition of simple spots ; 

 in others it fused them into lines and patches, and in some they 

 were entirely obliterated, as in the adult Puma and others. 



The intervals between the Jaguar and Leopard rosettes now 

 altered, as I said, through innumerable generations would seem to 

 indicate the sutures between the armour-plate rosettes of some 

 ancestral Glyptodontoid animal. 



Of course the skin of the Jaguar is elastic and mobile, and 

 stretches readily to adapt itself to the growing animal and to the 

 different variations in size which we see in the Cat tribe. Its elas- 

 ticity would seem sufficient to account for the broadening of the 

 network of sutures which we see everywhere between the Jaguar 

 rosettes, and perhaps also for the dissociation of the spotlets which 



1 In the Natural History Museum there is an interesting series of skins of Lacertilia ; 

 some have fully ossified scales, others have only vestiges of ossification. 



