610 TRANSACTIONS OF SECTION D. 



P. longicornis, and the working of legs aud abdomen for righting is much better 

 coordinated ; this enables us to understand the facts, noticed by Milne Edwards 

 and Bouvier, that P. longicornis has a long chain of abdominal ganglia,, but that 

 these are gathered up into the thorax and more concentrated in P. platycheles. 



2, Some Noles on the Mammalian Mandible. 

 By Professor Richard John Anderson, M.D. 



The size and shape of the mandible in Mammalia seem to depend mainly 

 on : — 



1. The size of the angle between the basioccipital and spinal axis. 



2. The size and character of the teeth. 



.3. The nature of the muscle attachments. 



4. The extent and kind of the movements. 



5. The conditions of the parts beneath and in its neighbourhood. 



.3. A Note on the Manus of the Doljjhin. 

 By Professor Richard John Anderson, M.D. 



The number of phalanges, which seems to vary, is made up of the normal 

 phalanges, which have each one or two epiphyses and pseudo-phalanges which 

 owe their existence to a deposit of osseous matter beyond the normal phalanges. 

 This deposit is probably due to the length of the flipper and the thickness of its 

 tissue, and the subdivisions probably bear some relation to the tenuity. 



