LECT. VII.] OLD REMNANTS IN NEW TYPES. 181 



from a low, and most probably a gill-bearing, amphibian 

 ancestry. Does sued an amphibian character as this 

 remarkable supporting splint-bone of the skull ever 

 turn up in the Mammalian class ? It is found in 

 this very Flying Cat I am speaking about; it has 

 a rudiment of the blade, exactly like that of a 

 Lizard, and I know of no other Mammal with this 

 most important rudiment. But, long ago, in the 

 most stupid and ancient of the Eodents or gnaw- 

 ing animals, a South American type the Guinea-Pig 

 I found large remnants, right and left, of the guard; and 

 lesser rudiments of this part in the Eabbit, the Hyrax, 

 and also in Man. Every student of human anatomy 

 knows that, besides the various bony centres that are 

 formed in the cartilaginous basis cranii under the pitui- 

 tary body, there is a free, independent nucleus, right and 

 left, in the angle formed by the base and wing of the pos- 

 terior sphenoid. This is just where the os petrosum or 

 stony bone of the ear-labyrinth is wedged in, and where 

 the internal carotid arteries enter ; these bones are 

 called the " lingulse sphenoidales," or little tongue-like 

 processes of the sphenoid bone. Let it be conceded, 

 then, that in the Mammalian skull, from that of the 

 Flying Cat up to that of Man, remnants of the para- 

 sphenoid of Ganoids, Dipnoi (double-breathing Fishes), 

 and Amphibians are found, and you open a door to the 

 most daring Darwinian speculations ever promulgated. 

 The Khynchocyon is a much more intelligible beast 



