Xil 



EXPLANATION OF THE FIGURES. 



The CHART OF ZOOLOGICAL REGIONS, page 370, is intended to show 

 the limits of the several Faunas of the American Continent, corresponding 

 to the climatal regions. As the higher regions of the mountains cor- 

 respond in temperature to the climate of higher latitudes, it will be seeu 

 that the northern temperate fauna extends, along the mountains of Mexico 

 and Central America, much farther towards the Equator, than it does on 

 the lower levels. In the same manner, the southern warm fauna extends 

 northward, along the Andes. 



Fig. 



1 Tissue of the house leek- Agassiz 



2 Pith of the elder . Ibid. 



3 Microscopic structure of carti- 



lage . . . Schwann 



4 Branchial cartilage of the larva 



of a frog . . Ibid. 



5 Evolution of cellular tissue. Ibid. 



6 Evolution of muscular fibre. Ibid. 



7 Evolution of nervous fibre. Ibid. 



8 Nucleated cells from the granula- 

 tions of the umbilical cord. Breschet 



9 Primary fibres of a human 



nerve . . . Wagner 



10 Branch of a nerve distributed to 



a muscle of the eye . Ibid. 



11 Primary fibres of the olfactory 



nerve in man . Valentin 



12 Terminal plexus of the auditory 



nerve (pike) . . Wagner 



13 Terminal plexus from the ciliary 



ligament (duck) . Valentin 



14 Terminal fibres (central) from 



the yellow substance of the ce- 

 rebellum . . Wagner 



15 Abdominal ganglion of the sym- 



pathetic nerve . . Ibid. 



16 Primary fibres of the intercostal 



nerve of the sparrow . Ibid. 



17 Thin slice from the cervical 



ganglion of the calf. Valentin 



18 Primary fibres and ganglionic glo- 



bules of the human brain. Ibid. 



19 The nervous system of Man. 



[Milne Edwards 



20 A section of the human brain, 



shewing likewise the point of 

 union of the cerebral nerves 

 therewith . . Ibid 



21 The brain and spinal cord of 



the Cyprinu& aiburnus. Cams 



Fig. 



21*A portion of the spinal cord shew- 

 ing the double union of the 

 nerves . . Edwards 



22 The brain of the eel seen from 



above . . . Carus 



23 The brain of the eel seen from 



below . . . Ibid. 



24 The brain of the tortoise seen 



from above . . Bojanus 



25 The brain of the tortoise seen 



from below . . Ibid. 



26 The brain of the turkey seen from 



above . . . Carus 



27 The brain of the pigeon seen 



from below . . Ibid. 



28 The brain and spinal cord of 



the rat ... Ibid. 



29 The brain of the hare . Ibid. 



30 The brain of the common cat. Ibid. 



31 The brain and spinal cord of 



the racoon . . Ibid. 



32 The brain of a monkey laid 



open .... Ibid. 



33 The brain of a monkey seen 



from below . . Ibid. 



34 The nervous system of the gar- 



den beetle . . . Ibid, 



35 The nervous system of Pa- 



hidina vivipara . Cuvier 



36 The nervous system of the star- 



fish . . Tiedeman 



37 Section of the globe of the 



eye . . . Agassiz 



38 Diagram shewing the effect of 



the eye on rays of light. Wagner 



39 Diagram shewing the effect of 



the eye on rays of light. Wagner 



40 Ditto ditto . . Ibid. 



41 Ditto ditto . . Ibid. 



42 Ditto ditto Ibid 



