276 Proceedings of the Royal Society of Victoria. 



5, increases as nerve XI. decreases, also nerve VIII., thicknesses 

 6 and 7. 



11. Nerve XI. and IV. show only a slight relation to one 

 another. As nerve XI. decreases in thickness, the frequency 

 of thickness 3 of nerve IV. increases, reaching its maximum 

 with nerve XI., thickness 2. Independently of irregularities in 

 nerve XI., thickness 1, due probably to the small number of 

 observations here, we find that the frequency of thicknesses 4 

 and 5 of nerve IV. tend to decrease with decreasing thickness 

 of nerve XI., so that it would appear that nerve IV. decreases 

 with a decreasing thickness of nerve XI. 



12. Nerves XI. and III. vary very irregularly, the pei'centages 

 showing no constant progression. The table shows that the 

 highest thickness 19 of nerve III. is found with a lower thickness 

 (2) of nerve XI., than is the lowest thickness (7) of nerve 3. 

 This may be taken to indicate the fact that while nerve XI. 

 decreases nerve III. increases, but since there are but few 

 observations for those particular thicknesses, it is doubtful how 

 much reliance can be placed on this. 



13. The only definite relations shown by this table to exist 

 between nerves XL and II. is the fact that the smallest thick- 

 ness (3) of II. only exists with the three smallest thicknesses 

 of nerve XI. The converse is not, however, by any means true. 

 Further, the frequency of the occurrence of intermediate thick- 

 nesses gives no information whatever on the variations of nerves 

 XI. and II. The highest thickness, however, 6, of nerve II., does 

 not occur with the two lowest thicknesses of nerve XL Therefore, 

 probably while nerve XL diminishes, nerve II. diminishes also. 



14. As X. decreases, IX. tends to increase. The two 

 smallest thicknesses of nerve X. are only found with the four 

 highest thicknesses of nerve IX., and rather more frequently 

 with the two highest, 11 and 16, of nerve IX. 



15. While X. decreases, VIII. increases. The percentage 

 relations are somewhat irregular ; but it will be seen that nerve 

 VIII., thickness 4, reaches a maximum with nerve X., thickness 

 9 ; and nerve VIIL, thickness 5, with nerve. X., thickness 5 

 (omitting thicknesses 3, 11, and 12, of nerve X., in which there 

 is but a single occurrence), while nerve VIIL, thickness 6, has 

 its maximum with nerve X., thickness 4; also nerve VIIL, 

 thicknesses 7 and 8, occur chiefly with a lower thickness of 



