294 Proceedings of the Royal Society of Victoria. 



Nerve XII. is again absent. 



All the specimens have the ileohypogastric composed of VIII. 

 fibres only as in Fig. 1, form iii., i.e., at its highest present state, 

 of advancement. When nerve VIII. has thickness 3, nerve IX. 

 thickness 5, and nerve X. thickness 6, we find the cruralis in the 

 condition drawn in Fig. 2, form v. It consists therefore of equal 

 quantities of nerves VIII. and IX., with no other fibres : X. 

 being absent. With nerve VIII. thicknesses 4 and 3, nerve IX. 

 thickness 9, and nerve X. thicknesses 6 and 4, the cruralis 

 finds its highest development, i.e., it contains only fibres from 

 nerve VIII. {vide Fig. 2, form viii.). 



In all forms, the sciatic has also reached nearly its highest 

 point of development as. shown in Fig. 3, form iv., nerves IX. 

 and X. sending equal quantities of fibres to it together with some 

 from VIII. Nerve tibres from XL are absent from the sciatic, 

 that nerve (XL) having reached its highest stage, as in Fig. 4, 

 form iii. In the brachial plexus we find with nerve IV. 

 thicknesses 7 and 3 and nerve III. thickness 5, nerve IV. 

 is fused with III. for some distance, Fig. 5, form iv., while 

 we get a branch between III. and IV., Fig. 5, form ii., with 

 nerve III. thickness 8, and nerve IV. thickness 4. When we 

 have nerve III. thicknesses 8 and 5, we find Fig. 6, form 

 iii., i.e., that II. is free from III., and with nerve III. 

 thickness 5 we have a branch between II. and TIL, i.e., Fig. 6, 

 form iii. 



The following observations were made on Limnodynastes 

 ornatus. The thicknesses of the nerves were these : — 



